Friday, December 27, 2013

Simple Voltage controlled current source with grounded source and load

This is a Simple Voltage controlled current source with grounded source and load. This is a simple, precise voltage-controlled current source. Bipolar supplies will permit bipolar output. Configurations featuring a grounded voltage- control source and a grounded load are usually more complex and depend upon several components for stability.Voltage-controlled-current-source-with-grounded-source-and-load. In this circuit, accuracy and stability almost entirely depend upon the 100-0 shunt.

Voltage controlled current source circuit diagram

Simple Voltage controlled current source with grounded source and load


Sourced by : Simple Voltage controlled current source with grounded source and load
Continue Reading..

Thursday, December 26, 2013

The omnidirectional antenna of cell phone jammer is common in normal use

U-Max Dingweizhixing business based on the positioning of mobile terminals, combined with GIS map data, can provide users with a wealth of location information services.
Unicom currently charges for mobile data communication standard is 0.01 yuan / kB. We are here to tell us through an example of the use of GPS: enter the Dingweizhixing Kyocera KZ850 function, select the "Where am I," later KZ850 will appear on the screen with a satellite picture, after a few seconds to ten seconds query time, the screen will display a description of the current location of mobile phones, such as "Wanquanhe Road, Wan new home near the new" kind of statement, then the user can further query the current location of the map, go a transfer to bus route, 500 meters to 2000 meters of restaurants, entertainment venues and so on. If getting through a call in the non-shielding area and walking into the shielding area, normally the cell phone will be shielded by cell phone jammer completely after covering a certain distance in the shielding area.The omnidirectional antenna of cell phone jammer is common in normal use.
The cost of this program is the GPS of 1 / 3. But by the mobile base station network resource constraints, continuous positioning in the high cost. Business management of employees; to provide for the sale of the company with multiple divisions, the sales staff working hours to work management; for remote decoding, where the phone number or other fixed internal procedures, to bind his number, binding After you can not limit the distance of the monitor, intercept, locate function. Electronic Technology Co., Ltd. Zhejiang left China Telecom is the only mobile location partners, using the most advanced, most accurate positioning technology GPSONE patrol, inspection, logistics, field / sales personnel management to provide efficient solutions. The directional antenna information of cell phone jammer should be described in details.
GPS company has many years experience in R & D and services, to provide car GPS and mobile positioning services. Digital Star is to develop mobile phone or terminal location and mobile application software company, its products and support the positioning of mobile phones and mobile phone also supports positioned between the display [2]. Is also the location of the earliest to provide mobile phone services company, mainly friends of the communitys position. Coverage had reached up to eight provinces. Cooperation with Henan MCC, mainly for business users, mobile location services platform. Coverage of Henan Province. Established in 2001, the first main GIS and telecommunications value-added services. Location networks Web site to provide mobile location-based services for enterprise and individual users. Coverage of 32 provinces and cities across the country.
Continue Reading..

Wednesday, December 25, 2013

Variable 5 to 20V DC Supply Rise

This is a Variable 5 to 20V DC Supply Circuit Diagram. If you are looking for a low drop voltage regulator that can provide a power supply of 1A with an output voltage of between 5V and 20V DC, National Semiconductor LM2941 Low Dropout Adjustable Regulator is that you can pick to make use of. Its a typical dropout voltage of 0.5V which means that the input supply need only must be 0.5V DC over the desired output voltage. 

Variable 5 to 20V DC Supply Circuit Diagram

Variable 5 to 20V DC Supply Circuit Diagram
 
Its other features include internal short circuit current limit and reverse battery protection. As shown in the schematic below, the regulator has five pins which consists of the ON/OFF control, Input Voltage, Output Voltage, Ground & Adjustable pins. ON/OFF is used for the purpose of switching on & off of the regulator. The capacitors C1 & E1 are to be placed as close as feasible to the regulator. 

The output of the circuit can be varied by varying the worth of potentiometer VR1 from 5V DC to 20V DC. The input voltage is limited from five.5V DC to 30V DC. Resistor R1 must be greater than 1K. The worth of the VR1 that needs to be set is calculated from the formula given below: 

VR1 = R1[(Vout/1.275) - 1] ohm
 If R1=1K, Vout = 5V, VR1 should be set to 2.9K ohm. 
 If R1=1K, Vout = 20V, VR1 should be set to 14.7K ohm


Continue Reading..

Tuesday, December 24, 2013

The assembly description is included in the working instruction

The assembly description is included in the working instruction of cell phone jammer .
A long-term study of electronic products on the impact of environmental pollution experts, a cell phone battery pollution load of waste, equivalent to 100 ordinary batteries. Used as a traditional cell phone, contain potentially harmful substances to the environment at least 20 species. Researchers have made an experiment, an old cell phone batteries, can contaminate 60,000 liters of water. "60,000 liters of water enough to fill three standard swimming pool." Cell phone batteries on the market today, the main points of nickel-cadmium batteries, nickel metal hydride batteries and lithium-ion battery 3 species. "One of nickel-cadmium batteries contain heavy metals as cadmium, harmful to human body. Have long contaminated, there may be emphysema, bone changes, anemia and other symptoms and may even lead to paralysis." The experts just such an account: reset the cell phone, the average life of 5 years (excluding its been sold several times in fact, not many cell phones can be used for 5 years. the authority of environmental protection organizations in Hong Kong a statistical average life of a cell phone for 600 days), each cell phone only one battery. Hefei urban resident population of 300 million or more (according to the Hefei Economic and Social Statistics Report 2009), calculated according to three million.As the recycling of used batteries can not find the departments and enterprises, recycling of used batteries often encounter "homeless" situation. Such as Jinan Ginza shopping on duty since 1998, recycling of used batteries, so far has recovered hundreds of thousands of festival, in addition to a business as part of the treatment trial, the rest still on the mall. Beijing was established in 1998 the usefulness of garbage recycling center, over the years has collected 400 tons of used batteries, still has most of the stack containers in the recycling center [4]. Recycling of used batteries only to move a home together in one place, but the pollution itself, this method is not desirable. cell phone jammer still can be used in such serious locations as the party and government institutions, theaters and so on which need tranquility.cell phone jammer components mainly include: main machinery, antenna, power supply adapter. Recycling of waste batteries has been difficult to handle, it is because our country has not yet established a comprehensive network and system for efficient recycling, waste battery processing industry has not established a set of industry, large-scale and specialized mode of operation. Although various types of waste processing technology has a lot of batteries, but some of the more mature, but a variety of economic factors constraining the development of battery disposal industry. Low recovery rate for disposal of batteries, long cycle efficiency is difficult to have too many economic benefits, even profitable, but also lose money, it is difficult to attract investors, so it is difficult to form an industrial scale, the scale can not be without realization of benefits.
Continue Reading..

Monday, December 23, 2013

Solar Powered Lithium Ion Battery Charger

The circuit below feeds a controlled current and voltage to a 3.6v lithium ion battery. The current is limited to 300ma and the voltage is limited to 4.2 volts. The circuit uses a LTC1734 IC from Linear Technology. No diode is needed between the circuit and a 6 volt solar panel. Some very nice 6 volt solar panels are available from www.plastecs.com Their SP6-200-12 cranks out about 1 watt while the SP6-300-12 can produce about 2 watts. Assuming a 6 hour sunlit day, the 2 watt panel will pump about 1.8 amp-hours into a battery.

Circuit Project: Circuit Solar Powered Lithium Ion Battery Charger
Continue Reading..

Sunday, December 22, 2013

Single Supply Function Generator

The circuit has both square-wave and triangle-wave output. The left section is similar in function to a comparator circuit that uses positive feedback for hysteresis. The inverting input is biased at one-half the Vcc voltage by resistor R4 and R5. The output is fed back to the non-inverting input of the first stage to control the frequency.

Circuit diagram :



Single Supply Function Generator Circuit Diagram

The amplitude of the square wave is the output swing of the first stage, which is 8V peak-to-peak. The second stage is basically an op amp integrator.

The resistor R3 is the input element and capacitor C1 is the feedback element.

The ratio R1/R2 sets the amplitude of the triangle wave, as referenced to the square-wave output. For both waveforms, the frequency of oscillation can be determined by the equation: fo= 1/4R3C1 * R2/R1

The output frequency is approximately 50 Hz with the given components.
Continue Reading..

Saturday, December 21, 2013

Here is the product performance of cell phone jammer

Here is the product performance of  cell phone jammer .
PIN code (Personal the Identity Number The Personal Identification Number) is a 4-bit to 8-bit personal to enter a password, also known as the PIN1 code, the user only enter this code, your phone to the SIM card to access the data. Belong to the SIM card password to protect the security of the SIM card. The initial PIN code, SIM card, usually set to 1234, the user can change it easy to remember the number. Attention to modify the PIN code must be firmly in mind, and do not remember in the mobile phone. PIN code, the main role is to prevent the SIM card is lost stolen to fight the phenomenon. Start a PIN code security function on the phone every time a user after a reboot. Here is the ambient temperature of  cell phone jammer .
GSM system must be between the phone and automatically identify and determine the legitimacy of the SIM card and mobile phone on the "password", the only system approved in order for the user to provide services. If the user is a continuous three incorrect PIN code, SIM card will be locked, must re-initialized in order to use the telecommunications sector. The PUK (PIN Unlocking the Key, unlock code) is the key to the solution PIN code lock. If you have three consecutive entered the wrong PIN, the phone will self-lock card, then you must enter the correct PUK code to unlock card lock, and then prompted to set a new PIN code. If the PUK code for mismatched 10 times, then the SIM card of the suicide program will start automatically, the card will be scrapped, only changing the card. PUK code is provided by the carriers operating room.
Best 3 to 5 times the manufacturers recommend the initial use of the battery to fully charge and discharge process, in order to eliminate electrode materials passivation, to achieve maximum capacity. Promulgated in 2001, three nickel-metal hydride nickel-cadmium and lithium-ion battery, GB have clear provisions in the detection of its initial capacity, the battery can be five times the deep charge deep-release, once required, the test can be stopped. This is a good explanation of this phenomenon I said so, said the second activation is also possible, the user first used the "new" battery as far as possible several deep discharge cycle. However, according to my tests (for lithium-ion battery), storage of 1 to 3 months lithium-ion battery.  cell phone jammer has the advantage of convenient use.It is towards the heat dissipation of cell phone jammer
It deep charge deep-release cycle of treatment, its capacity to improve the phenomenon is almost non-existent (in the symposium on the battery to activate the test report). Three secondary charge 12 hours. This issue is closely linked to the above battery activation, tentatively set to the factory battery to the user hand electrode passivation phenomena, deep charge deep discharge cycles in order to activate the battery 3 times. In fact, this problem is transformed into a deep charge is not to charge 12 hours. I have another article on the cell phone battery charging time has answered this question the answer is no need to charge 12 hours. the early days of mobile phone nickel-metal hydride battery because of the need to complement and trickle charge process to achieve the most perfect state of full charge , you may need about five hours.  cell phone jammer is the ideal shielding equipment for actively preventing cheating.
Continue Reading..

Friday, December 20, 2013

When cell phone jammer switches on and starts working

 When cell phone jammer switches on and starts working.
The shell mold cavity and core materials to use wear high hardness mirror mold steel. Mold also good material intensity and use standard mold base, another like the top tube mandrel also use the standard, in order to improve the quality and speed of the mold manufacturing. The choice of mold material, specifically to see the Table of the chapter of the book material. Materials, heat treatment of the mold material. Means of heat treatment of the mold material heat treatment of plastic mold materials commonly used in tempering, carburizing, quenching. The heat treatment is conducive to metal machining, to improve the machining accuracy, surface hardness, wear resistance and stability. For example, we can often see a phenomenon: the new mold parts to do good, do 1-2 million. It is convenient to charge cell phone jammer .Faults of cell phone jammer can be solved as soon as possible
Open before and after the shell will damage the lack of any assembly of components can not be missing any parts assembly prototype hooks, and shell assembly, the parts must be complete, experience tells us: that the parts often less fitted, after that part is a problem. And structure of the assembly not only focus on the assembly structure, the same concern with the structure of the PCBA and connector, and a large, high components. A good approach is in strict accordance with the BOM and assembly diagram to do, so easy to find problems. Measurement and assembly of prototype size you want real-time to make a record, otherwise easily forgotten. Specific assembly and test Table 2-5 phone prototype structure assembly Checklist prototype assembly inspection is not only a product quality inspection.
Missed drop is the actual accident situation occurs most frequently use their mobile phones, drop test reliability of the test structure design stiffness and strength test. In the drop test height of 1m, the force is about 10 times its weight chassis, so a good estimate of the structural parts and packaging design stiffness and strength. The drop is more common to test the battery off, so the shell of the card after the battery into the structure of the extrusion force is to be strictly calculated. The structural design of these trials need to understand the methods and principles to guide the design and improvement of the design. The content of these trials the implementation of the responsibility of the professional engineers of the quality management department. The workshop has issued the newest model of cell phone jammer .It is along the thread on the host of cell phone jammer
Continue Reading..

Thursday, December 19, 2013

5V Power Supply Using LTM8021

This 5v power supply circuit is designed using the LTM8021 and will provide a maximum current up to 500mA. Almost all required parts are included in the LTM8021 package. This 5v power supply circuit based on the LTM8021 operate over a input voltage range between 3V and 36V .The LTM8021 supports an output voltage range of 0.8V to 5V, set by a single resistor. Only an output and bulk input capacitor are needed to finish the design.

5V Power Supply Circuit diagram


Continue Reading..

Wednesday, December 18, 2013

Car Cigar Lighter to USB Power Socket

Nowadays, almost all computer systems have logic blocks for working with a USB port. A USB port, in practice, is capable of supplying more than 100 mA of continuous electric current at 5V to the peripherals which are hooked up with the bus. So a USB port could be utilized, without having any problems, for powering 5V DC operated tiny electronic devices.

Cigar-Plug-USB-Power-Socket Circuit diagram
Today, a lot of handheld gadgets (for example, portable reading lamps) utilise this resource of the USB port to recharge their built-in battery pack using the support of an internal circuitry. Typically 5V DC, 100mA electric current is needed to satisfy the input electrical power demand. The above diagram shows the circuit of a versatile USB power socket that properly converts the 12V battery voltage into stable 5V. This circuit can make it possible to power / recharge any USB power-operated device, working with in-dash board cigar lighter socket of the car.

usb qwe
The DC supply presented from the cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1).
Usb Pin 
Capacitor C1 buffers any disorder in the input supply. Resistors R1 and R2 regulate the output of IC1 to constant 5V, that is accessible at the ‘A’ type female USB socket. Red LED1 signifies the output condition and zener diode ZD1 acts as a protector against excessive voltage. Assemble the circuit on a general purpose PCB and enclose inside a slim plastic cabinet as well as the indicator and USB socket. Whilst wiring the USB outlet, make sure proper polarity of the supply. For interconnection between the cigar plug pin as well as the device, use a long coil cord as shown in second image.

Source: http://www.ecircuitslab.com/2012/07/car-cigar-lighter-to-usb-power-socket.html
Continue Reading..

Tuesday, December 17, 2013

Simple Self Oscillating Switching Converter Circuit Diagram

This is a Simple Self Oscillating Switching Converter Circuit Diagram. Regulation is provided by taking the rectified output of the sense winding and applying it as a bias to the base of Q2 via zener Dl. The collector of Q2 then removes drive from the gate of Ql. 

Therefore, if the . output voltage should increase, Q2 removes the drive to Ql earlier, shortening the on time, and the output voltage will remain the same. De outputs are obtained by merely rectifying and filtering secondary windings, as done by D5 and C4.

Self Oscillating Switching Converter Circuit Diagram

Simple Self Oscillating Switching Converter Circuit Diagram

Continue Reading..

Thursday, October 10, 2013

Fastest Finger First Indicator

Quiz-type game shows are increasingly becoming popular on television these days. In such games, fastest finger first indicators (FFFIs) are used to test the player’s reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button. The circuit presented here determines as to which of the four contestants first pressed the button and locks out the remaining three entries. Simultaneously, an audio alarm and the correct decimal number display of the corresponding contestant are activated. When a contestant presses his switch, the corresponding output of latch IC2 (7475) changes its logic state from 1 to 0. The combinational circuitry comprising dual 4-input NAND gates of IC3 (7420) locks out subsequent entries by producing the appropriate latch-disable signal. Priority encoder IC4 (74147) encodes the active-low input condition into the corresponding binary coded decimal (BCD) number output.

Fastest Finger First Indicator Circuit DiagramThe outputs of IC4 after inversion by inverter gates inside hex inverter 74LS04 (IC5) are coupled to BCD-to-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common-anode 7-segment LED display (DIS.1, FND507 or LT542). The audio alarm generator comprises clock oscillator IC7 (555), whose output drives a loudspeaker. The oscillator frequency can be varied with the help of preset VR1. Logic 0 state at one of the outputs of IC2 produces logic 1 input condition at pin 4 of IC7, thereby enabling the audio oscillator. IC7 needs +12V DC supply for sufficient alarm level. The remaining circuit operates on regulated +5V DC supply, which is obtained using IC1 (7805). Once the organiser identifies the contestant who pressed the switch first, he disables the audio alarm and at the same time forces the digital display to ‘0’ by pressing reset pushbutton S5. With a slight modification, this circuit can accommodate more than four contestants.
Continue Reading..

Wednesday, October 9, 2013

Lights On!

This circuit ensures that you will never again forget to switch on the lights of your car. As soon as the engine is running, the dipped beams and the sidelights are automatically switched on. The circuit also causes the dipped beams to be extinguished as soon as the main beams are switched on. As you can see from the schematic diagram, no special components are needed. When the engine is running, the alternator will generate a voltage of more than 14 V. Diode D1 reduces this voltage by 5.6 V and passes it to the base of T1 via R1. Due to the resulting current, T1 conducts. The amplified current flows via R3, the base of T3 and D3 to ground. This causes T3 to also conduct and energize relay Re1.

Circuit diagram :

Lights_On_Circuit_DiagramLights On Circuit Diagram

If the driver now switches on the main beams, a current flows through D2 and R2 into the base of T2, causing this transistor to conduct. As a result, the voltage on the base of T3 drops, causing T3 to cut off and the relay to drop out. When the main beams are switched off, the previous situation is restored, and the relay again engages. The dipped beams and the sidelights are switched by the contacts of relay Re1. Diodes D5 and D6 ensure that the sidelights are illuminated if either the dimmed beams or the main beams are switched on. In practice, this means that the sidelights will be on whenever the engine is running, regardless of whether the main beams are switched on.

Source : www.extremecircuits.net

Continue Reading..

Tuesday, October 8, 2013

Reset Sequencer

It is often necessary in complex designs to provide a sequence of reset pulses to different parts of a circuit to ensure the whole design functions reliably. The DS1830 from Maxim (www.maxim-ic.com) provides three sequenced open-drain reset outputs. This chip is designed for 5 V systems but a 3.3 V version (DS1830A) is also available. Both are offered in a range of package outlines including DIP, SO and µSOP. Two inputs give the chip some degree of programmability of its characteristics: The TOL input defines the chips tolerance to power supply fluctuations before a reset sequence is triggered.


Jumper JP1 allows the TOL to be connected to Ub (Vcc), ground or left open circuit and will result in the following three reset thresholds: The TD input allows the length of the reset signal to be programmed and jumper JP2 gives the following three possibilities: The PBRST (pushbutton reset) allows a manual reset button to be connected to the chip. This input has a built-in 40 k? pull up resistor and can also be driven by a digital output or used to cascade additional devices to provide more sequenced reset signals.
Continue Reading..

Monday, October 7, 2013

Rear Fog Lamp For Vintage Cars

According to current legislation in many countries, vintage cars must also be fitted with a fog lamp at the rear. In modern cars, there is a bit of circuitry associated with the fog lamp switch to prevent the fog lamp from going on when the lights are switched on if the driver forgot to switch it off after the last patch of fog cleared up. The circuit described here extends that technology back in time. The circuit is built around a dual JK flip-flop (type 4027). T3 acts as an emitter follower, and it only supplies power to the circuit when the lights are switched on.

For safety reasons, the supply voltage is tapped off from the number plate lamp (L2), because it is on even if you accidentally drive with only the parking lights on. The wire that leads to the number plate lamp usually originates at the fuse box. As the states of the outputs of IC1a and IC1b are arbitrary when power is switched on, the reset inputs are briefly set high by the combination of C1, R1 and T1 when the lights are switched on (ignition switch on). That causes both Q outputs (pins 1 and 15) to go low. IC1a and IC1b are wired in toggle mode (J and K high).

The Set inputs are tied to ground (inactive). The driver uses pushbutton switch S1 to generate a clock pulse that causes the outputs of the flip-flops to toggle. The debouncing circuit formed by C2, R4 and T2 is essential for obtaining a clean clock pulse, and thus for reliable operation of the circuit. C1 and C2 should preferably be tantalum capacitors. The Q output of IC1b directly drives LED D1 (a low-current type, and yellow according to the regulations). The Q output of IC1a energises relay Re1 via T4 and thus applies power to the rear fog lamp L1.

Circuit diagram:

rear-fog-lamp-for-vintage-cars-circuit-diagram

Rear Fog Lamp Circuit Diagram For Vintage Cars

Free-wheeling diode D2 protects T4 against inductive voltage spikes that occur when the relay is de-energised. In older-model cars, the charging voltage of the generator or alternator is governed by a mechanical voltage regulator. These regulators are less reliable than the electronic versions used in modern cars. For that reason, a Zener diode voltage-limiter circuit (D3 and R9) is included to keep the voltage at the emitter of T3 below 15 V and thus prevent the 4027 from being destroyed by an excessively high voltage.

The supply voltage for the circuit is tapped off from the fuse box. An accessory terminal is usually present there. Check to make sure it is fed from the ignition switch. The pushbutton switch must be a momentary-contact type (not a latching type). Ensure that the pushbutton and LED have a good ground connection. Fit the LED close to the button.

The following ‘Bosch codes’ are used in the schematic:

  • 15 = +12 V from ignition switch
  • 58K = number plate lamp
  • 86 = relay coil power (+) IN
  • 85 = relay coil power OUT
  • 30 = relay contact (+) IN
  • 87 = relay contact OUT

Author: Eric Vanderseypen - Copyright: Elektor Electronics Magazine

Continue Reading..

Sunday, October 6, 2013

Speed Limit Alert

Wireless portable unit, Adaptable with most internal combustion engine vehicles

This circuit has been designed to alert the vehicle driver that he/she has reached the maximum fixed speed limit (i.e. in a motorway). It eliminates the necessity of looking at the tachometer and to be distracted from driving. There is a strict relation between engines RPM and vehicle speed, so this device controls RPM, starting to beep and flashing a LED once per second, when maximum fixed speed is reached. Its outstanding feature lies in the fact that no connection is required from circuit to engine.

Circuit operation:

IC1 forms a differential amplifier for the electromagnetic pulses generated by the engine sparking-plugs, picked-up by sensor coil L1. IC2A further amplifies the pulses and IC2B to IC2F inverters provide clean pulse squaring. The monostable multivibrator IC3A is used as a frequency discriminator, its pin 6 going firmly high when speed limit (settled by R11) is reached. IC3B, the transistors and associate components provide timings for the signaling part, formed by LED D5 and piezo sounder BZ1. D3 introduces a small amount of hysteresis.

Circuit diagram:

Speed-limit Alert Circuit Diagram

Speed-limit Alert Circuit Diagram

Parts:

R1,R2,R19_______1K 1/4W Resistors
R3-R6,R13,R17_100K 1/4W Resistors
R7,R15__________1M 1/4W Resistors
R8_____________50K 1/2W Trimmer Cermet
R9____________470R 1/4W Resistor
R10___________470K 1/4W Resistor
R11___________100K 1/2W Trimmer Cermet (see notes)
R12___________220K 1/4W Resistor (see notes)
R14,R16________68K 1/4W Resistors
R18____________22K 1/4W Resistor
R20___________150R 1/4W Resistor (see notes)
C1,C7_________100µF 25V Electrolytic Capacitors
C2,C3_________330nF 63V Polyester Capacitors
C4-C6___________4µ7 25V Electrolytic Capacitors
D1,D5______Red LEDs 3 or 5mm.
D2,D3________1N4148 75V 150mA Diodes
D4________BZX79C7V5 7.5V 500mW Zener Diode
IC1__________CA3140 or TL061 Op-amp IC
IC2____________4069 Hex Inverter IC
IC3____________4098 or 4528 Dual Monostable Multivibrator IC
Q1,Q2_________BC238 25V 100mA NPN Transistors
L1_____________10mH miniature Inductor (see notes)
BZ1___________Piezo sounder (incorporating 3KHz oscillator)
SW1____________SPST Slider Switch
B1_______________9V PP3 Battery (see notes) Clip for PP3 Battery

Notes:

  • D1 is necessary at set-up to monitor the sparking-plugs emission, thus allowing to find easily the best placement for the device on the dashboard or close to it. After the setting is done, D1 & R9 can be omitted or switched-off, with battery savings.
  • During the preceding operation R8 must be adjusted for better results. The best setting of this trimmer is usually obtained when its value lies between 10 and 20K.
  • You must do this first setting when the engine is on but the vehicle is stationary.
  • The final simplest setting can be made with the help of a second person. Drive the vehicle and reach the speed needed. The helper must adjust the trimmer R11 until the device operates the beeper and D5. Reducing vehicles speed the beep must stop.
  • L1 can be a 10mH small inductor usually sold in the form of a tiny rectangular plastic box. If you need an higher sensitivity you can build a special coil, winding 130 to 150 turns of 0.2 mm. enameled wire on a 5 cm. diameter former (e.g. a can). Extract the coil from the former and tape it with insulating tape making thus a stand-alone coil.
  • Current drawing is about 10mA. If you intend to use the car 12V battery, you can connect the device to the lighter socket. In this case R20 must be 330R.
  • Depending on the engines cylinders number, R11 can be unable to set the device properly. In some cases you must use R11=200K and R12=100K or less.
  • If you need to set-up the device on the bench, a sine or square wave variable generator is required.
  • To calculate the frequency relation to RPM in a four strokes engine you can use the following formula: Hz= (Number of cylinders * RPM) / 120.
  • For a two strokes engine the formula is: Hz= (Number of cylinders * RPM) / 60.
  • Thus, for a car with a four strokes engine and four cylinders the resulting frequency @ 3000 RPM is 100Hz.
  • Temporarily disconnect C2 from IC1 pin 6. Connect the generator output across C2 and Ground. Set the generator frequency to e.g. 100Hz and trim R11 until you will hear the beeps and LED D5 will start flashing. Reducing the frequency to 99 or 98 Hz, beeping and flashing must stop.
  • Please note that this circuit is not suited to Diesel engines.

Source : www.redcircuits.com

Continue Reading..

Saturday, October 5, 2013

Serial To Parallel Converter

This converter may help if just the serial port on a personal computer is free, whereas the printer needs a parallel (Centronics) port. It converts a serial 2400 baud signal into a parallel signal. The TxD line, pin 3, CTS line, pin 8 and the DSR line, pin 6, of the serial port are used - see diagram. The CTS and DSR signals enable handshaking to be implemented. Since the computer needs real RS232 levels, an adaptation from TTL to RS232 is provided in the converter by a MAX232. This is an integrated level converter that transforms the single +5V supply into a symmetrical ±12V on.

Serial-to-Parallel Converter Circuit Diagramw

The serial-to-parallel conversion is effected by IC1. This is essentially a programmed PIC controller that produces a Centronics compatible signal from a 2400 baud serial signal (eight data bits, no parity, one stop bit). The IC also generates the requisite control signals. If there is a delay on the Centronics port, the RS232 bitstream from the computer may be stopped via the Flow signal (pin 17). This ensures that no data is lost. The controller needs a 4 MHz ceramic resonator, X1.

Source : www.extremecircuits.net

Continue Reading..

Friday, October 4, 2013

A Discharger for Receiver Battery Packs

You may have read about cycling NiCad batteries. If not, read a little here ( Reds R/C Battery Clinic) for an excellent overview. Overcharging apparently leads to voltage depression, which can be corrected by one or two complete discharges (to 1 to 1.1 volts per cell). On the other hand, over discharging the batteries to a low or zero voltage can damage them, and if the batteries have not been overcharged and have no voltage depression, cycling just uses up regular battery life. I designed and use this discharger occasionally to remove voltage depression and insure battery capacity is still ok for those planes that have no low voltage alarm.

Note that the 100 ohm resistors are 1/2 watt (these are the load resistors), the rest are 1/4 watt. The red LED lights while discharging, buzzer sounds and discharge rate drops to 15-25mA (for the buzzer) when complete. The discharge load is 60mA to 110mA depending on the battery voltage. Since thats about the same current draw as my Hitec receiver and two HS-80s draw while flying handlaunch, I can use discharge time almost directly to indicate flying time. The buzzer uses enough current to keep a 150mA battery down, but when discharging a 600mA battery, the battery recovers quickly when the load is removed--the buzzer/discharger cycles on and off. Threshold voltage of the discharger is set to 4.2 volts. Since the discharger still draws some current when buzzing, try to disconnect the discharger once the alarm sounds--dont leave it going for hours lest the battery be over discharged.

Discharger for Receiver Battery Packs circuit

There are a couple ways you could modify the circuit to work with a 5-cell 6-volt receiver battery pack. The two 1k resistors are a divider network, so one way would be to change the resistors to change the sampling voltage at the comparator. The formula for a divider network is Vout=Vin(R2/(R1+R2)) or R1=R2*((Vin/Vout)-1). Here, R1 is the resistor connected to the positive lead and pin 7 of the comparator, Vin is 5.25 volts (1.05 volts per cell discharge shutoff threshold), and Vout is the reference 2.1 volts (the voltage produced by the LM317T and the 180 and 270 ohm resistors). You can use R2 as the same 1k value that was there before. So R1=1000*((5.25/2.1)-1)=1500=1.5k. So swap the top 1k resistor in the schematic for a 1.5k, and the new shutoff voltage for your device will be 5.25 volts.

To increase the discharge rate, decrease the resistance of the load resistors. You could use four 100 ohm resistors in parallel instead of two, for example, and it would discharge twice as fast. Resistance of a number of resistors in parallel is the value of the resistor devided by the number of the resistors. Here, 100 ohms/ four resistors is 25 ohms. At five volts, current is (5 volts)/(25 ohms)=0.2 ampere or 200mA. Be careful not to decrease resistance too much however--the small signal transistor used in this particular circuit is probably only rated for maximum 500 mA.

Circuit diagram :

Discharger for Receiver Battery Packs circuit 1 Discharger for Receiver Battery Packs1

Parts:
273-074 Miniature Piezo Buzzer, 12v, PC board mount
271-312 1/4 watt 5% carbon film resistors, 500 pieces (Just do it!)
276-1778 LM317T adjustable voltage regulator
276-1712 Quad comparator LM339
276-1622 LED assortment (20 count)
276-2009 NPN Silicon transistor MPS2222A (2N2222)

Custom electronics:
I post this design not because I think this is a brilliant piece of circuit design but because the design works, and it can give you a start on your own experimentation. The idea is to use the power available from the discharging battery to monitor the voltage of the battery, shut off discharging at a preset voltage (here 1.05 volts/cell), and sound an alarm when discharging is complete. To do so means a voltage reference powered by the changing voltage of the battery, here the LM317T and the 180 with 270 ohm resistors. You could just as easily use a LM336 (see the low voltage warning buzzer page) or a zener with resistor, or something else as a reference. Since the reference voltage must be below the ambient battery voltage, a pair of 1k resistors provides the divided test voltage. The LM339 is a four way comparator.
This design uses really three comparators: in addition to the one driving the transistor, a comparator drives the LED and another drives the buzzer. But you could use a single comparator (like the LM311) with the buzzer across the emitter and collector of the transistor, and the LED in series with a 270 ohm resistor across (parallel with) the 100 ohm load resistors. With the transistor conducting, the voltage drop across base and emitter is low, and the buzzer is quiet. The tiny current in a piezo buzzer (7 mA), when the transistor is not conducting, would be divided between the load resistors and the LED, and the LED is dark.
A word about the comparator. The output of the comparator serves as a meager source of current, but can sink current nicely. In other words, the high logic output of the comparator will not drive the base of a NPN transistor as here. The 560 ohm resistor provides the current here for the transistor base--the comparator takes it away when its output drops to ground. Hmmm . . . . so, maybe use a PNP transistor like a 2N3906 instead with emitter to + and collector to load, remove the 560 resistor and connect the base through a 1k resistor to the output of the comparator, then reverse the logic of the comparator by swapping the reference with the test. . . hmmmmm. Could work. Yep . . . works.

Source : electronic

Continue Reading..

Thursday, October 3, 2013

Mains Powered White LED Lamp

Did it ever occur to you that an array of white LEDs can be used as a small lamp for the living room? If not, read on. LED lamps are available ready-made, look exactly the same as standard halogen lamps and can be fitted in a standard 230-V light fitting. We opened one, and as expected, a capacitor has been used to drop the voltage from 230 V to the voltage suitable for the LEDs. This method is cheaper and smaller compared to using a transformer. The lamp uses only 1 watt and therefore also gives off less light than, say, a 20 W halogen lamp. The light is also somewhat bluer. The circuit operates in the following manner: C1 behaves as a voltage dropping ‘resistor’ and ensures that the current is not too high (about 12 mA).

Mains Operated White LED Lamp Circuit
The bridge rectifier turns the AC voltage into a DC voltage. LEDs can only operate from a DC voltage. They will even fail when the negative voltage is greater then 5 V. The electrolytic capacitor has a double function: it ensures that there is sufficient voltage to light the LEDs when the mains voltage is less than the forward voltage of the LEDs and it takes care of the inrush current peak that occurs when the mains is switched on. This current pulse could otherwise damage the LEDs. Then there is the 560-ohm resistor, it ensures that the current through the LED is more constant and therefore the light output is more uniform.

White LED Lamp Circuit Diagram
There is a voltage drop of 6.7 V across the 560-Ω resistor, that is, 12 mA flows through the LEDs. This is a safe value. The total voltage drop across the LEDs is therefore 15 LEDs times 3 V or about 45 V. The voltage across the electrolytic capacitor is a little more than 52V. To understand how C1 functions, we can calculate the impedance (that is, resistance to AC voltage) as follows: 1/(2π·f·C), or: 1/ (2·3.14·50·220·10-9)= 14k4. When we multiply this with 12 mA, we get a voltage drop across the capacitor of 173 V. This works quite well, since the 173-V capacitor voltage plus the 52-V LED voltage equals 225 V. Close enough to the mains voltage, which is officially 230 V.

Mains Powered White LED Lamp Circuit DiagramMoreover, the latter calculation is not very accurate because the mains voltage is in practice not quite sinusoidal. Furthermore, the mains voltage from which 50-V DC has been removed is far from sinusoidal. Finally, if you need lots of white LEDs then it is worth considering buying one of these lamps and smashing the bulb with a hammer (with a cloth or bag around the bulb to prevent flying glass!) and salvaging the LEDs from it. This can be much cheaper than buying individual LEDs…
Continue Reading..

Wednesday, October 2, 2013

Doorbell Cascade

Sometimes you have to do it the hard way, even if doing it the easy way is an option. That is the case here. The intention is to add a second doorbell in parallel with the existing bell. This does not, in principle, require any electronic components. You would simply connect the second bell to the first one. But if the existing bell transformer is not rated for the additional load then this is not a good idea! An option is to buy a new and larger transformer. But bigger also means more expensive! Moreover, replacing the existing transformer can be an awkward job, for example when it is built into the meter box. So we follow different approach.

Doorbell Cascade circuit schematic

This circuit is connected in parallel with the existing bell. This is possible because the current consumption is very small compared to the load of the bell. The bridge rectifier rectifies the bell voltage when the push-button is pressed. This will then close the relay contacts. These contacts are the ‘electronic’ button for the second bell,which is powered from its own cheap bell transformer.
Continue Reading..

Tuesday, October 1, 2013

Cheap 12V to 220V Inverter

Even though today’s electrical appliances are increasingly often self-powered, especially the portable ones you carry around when camping or holidaying in summer, you do still sometimes need a source of 230 V AC - and while we’re about it, why not at a frequency close to that of the mains? As long as the power required from such a source remains relatively low - here we’ve chosen 30 VA - it’s very easy to build an inverter with simple, cheap components that many electronics hobbyists may even already have.
Though it is possible to build a more powerful circuit, the complexity caused by the very heavy currents to be handled on the low-voltage side leads to circuits that would be out of place in this summer issue. Let’s not forget, for example, that just to get a meager 1 amp at 230 VAC, the battery primary side would have to handle more than 20 ADC!. The circuit diagram of our project is easy to follow. A classic 555 timer chip, identified as IC1, is configured as an astable multivibrator at a frequency close to 100 Hz, which can be adjusted accurately by means of potentiometer P1.
12-volt-to-230-volt-invertor-circuit-diagram
As the mark/space ratio (duty factor) of the 555 output is a long way from being 1:1 (50%), it is used to drive a D-type flip-flop produced using a CMOS type 4013 IC. This produces perfect complementary square-wave signals (i.e. in antiphase) on its Q and Q outputs suitable for driving the output power transistors. As the output current available from the CMOS 4013 is very small, Darlington power transistors are used to arrive at the necessary output current. We have chosen MJ3001s from the now defunct Motorola (only as a semi-conductor manufacturer, of course!) which are cheap and readily available, but any equivalent power Darlington could be used.
These drive a 230 V to 2 × 9 V center-tapped transformer used ‘backwards’ to produce the 230 V output. The presence of the 230 VAC voltage is indicated by a neon light, while a VDR (voltage dependent resistor) type S10K250 or S07K250 clips off the spikes and surges that may appear at the transistor switching points. The output signal this circuit produces is approximately a square wave; only approximately, since it is somewhat distorted by passing through the transformer. Fortunately, it is suitable for the majority of electrical devices it is capable of supplying, whether they be light bulbs, small motors, or power supplies for electronic devices.
PCB layout:
pcb-layout-12-volt-to-230-volt-invertor-circuit-diagram
COMPONENTS LIST
Resistors
R1 = 18k?
R2 = 3k3
R3 = 1k
R4,R5 = 1k?5
R6 = VDR S10K250 (or S07K250)
P1 = 100 k potentiometer
Capacitors
C1 = 330nF
C2 = 1000 µF 25V
Semiconductor
T1,T2 = MJ3001
IC1 = 555
IC2 = 4013
Miscellaneous
LA1 = neon light 230 V
F1 = fuse, 5A
TR1 = mains transformer, 2x9V 40VA (see text)
4 solder pins
Note that, even though the circuit is intended and designed for powering by a car battery, i.e. from 12 V, the transformer is specified with a 9 V primary. But at full power you need to allow for a voltage drop of around 3 V between the collector and emitter of the power transistors. This relatively high saturation voltage is in fact a ‘shortcoming’ common to all devices in Darlington configuration, which actually consists of two transistors in one case. We’re suggesting a PCB design to make it easy to construct this project; as the component overlay shows, the PCB only carries the low-power, low-voltage components.
The Darlington transistors should be fitted onto a finned anodized aluminum heat-sink using the standard insulating accessories of mica washers and shouldered washers, as their collectors are connected to the metal cans and would otherwise be short-circuited. An output power of 30 VA implies a current consumption of the order of 3 A from the 12 V battery at the ‘primary side’. So the wires connecting the collectors of the MJ3001s [1] T1 and T2 to the transformer primary, the emitters of T1 and T2 to the battery negative terminal, and the battery positive terminal to the transformer primary will need to have a minimum cross-sectional area of 2 mm2 so as to minimize voltage drop.
The transformer can be any 230 V to 2 × 9 V type, with an E/I iron core or toroidal, rated at around 40 VA. Properly constructed on the board shown here, the circuit should work at once, the only adjustment being to set the output to a frequency of 50 Hz with P1. You should keep in minds that the frequency stability of the 555 is fairly poor by today’s standards, so you shouldn’t rely on it to drive your radio-alarm correctly – but is such a device very useful or indeed desirable to have on holiday anyway? Watch out too for the fact that the output voltage of this inverter is just as dangerous as the mains from your domestic power sockets.
So you need to apply just the same safety rules! Also, the project should be enclosed in a sturdy ABS or diecast so no parts can be touched while in operation. The circuit should not be too difficult to adapt to other mains voltages or frequencies, for example 110 V, 115 V or 127 V, 60 Hz. The AC voltage requires a transformer with a different primary voltage (which here becomes the secondary), and the frequency, some adjusting of P1 and possibly minor changes to the values of timing components R1 and C1 on the 555.
Author : B. Broussas Copyright  Elektor Elecronics 2008
Continue Reading..

Monday, September 30, 2013

Preamplifier For Soundcard Circuit

This circuit can be used for inductive pick-up elements and dynamic microphones Most soundcards have a ‘line’ input and one for an electret (condenser) microphone. To be able to connect an inductive tape-recorder head or a dynamic microphone, an add-on preamplifier is needed. Even in this day and age of integrated microelectronics, a transistorised circuit built from discrete part has a right of existence. The preamplifier described in this short article goes to show that it will be some time before discrete transistors are part of the silicon heritage. The preamplifier is suitable for use with a soundcard or the microphone input of a modem. As you will probably know, most sound-cards have input sockets for signals at line level (stereo), as well as one for a (mono) electret microphone.
For the applications we have in mind, connecting-up an inductive pick-up element or a dynamic microphone, both inputs are in principle suitable, provided the source signal is amplified as required. The author eventually chose the microphone input on the soundcard. Firstly, because the line inputs are usually occupied, and secondly, because the bias voltage supplied by the micro-phone input eliminates a separate power supply for the preamplifier. The microphone input of a soundcard will typically consist of a 3.5-mm jack socket in stereo version, although only one channel is available. The free contact is used by the soundcard to supply a bias voltage to the mono electret microphone. This voltage is accepted with thanks by the present preamplifier, and conveniently obviates an external (mains adaptor) power supply.
Circuit diagram:
preamplifier-for-soundcard-circuit-diagramw
A classic design:
In true transistor-design fashion, the preamplifier consists of three stages. Capacitor C1 decouples the signal received from the microphone or pick-up element, and feeds it to the input of the first stage, a transistor in emitter configuration, biased to provide a current amplification of about 300 times. Together with the source impedance of the microphone or pick-up element, capacitors C2 and C3 form a low-pass filter which lightly reduces the bandwidth. In addition, the output low-pass, R2-C3, reduces the dynamic collector resistance at higher frequencies. In this way, the filter reduces the gain in the higher part of the frequency spectrum and so helps to eliminate any oscillation tendencies.
The first, high-gain, stage is terminated by T2. Unlike T1, this transistor does not add to the overall gain, because the output signal is taken from the emitter (common-collector circuit). T2 thus acts as an impedance converter, with C4 reducing any tendency to oscillation. The output stage around T3 is a common-emitter circuit again. In it, preset P1 determines the voltage amplification. T3 is biased by means of a direct-current feedback circuit based on components R7 and C5. To this is added an ‘overruling’ dc feedback path back to the input transistor, via R6. This measure guarantees good dc stability in the preamplifier. The circuit is small enough to be built on a piece of veroboard or stripboard, and yet remain reasonably compact.
To prevent interference from external sources, the completed board should be mounted in a properly screened (metal) enclosure, with the connections to the input source and the sound card made in screened cable. The preamplifier provides a frequency-linear response. In case the source signal is marked by frequency correction (e.g., RIAA), then a matching linearization circuit should be used if the relevant signals are used by the computer.
Continue Reading..

Sunday, September 29, 2013

Thrifty 2Hz Clock

CMOS circuits are known for their low current consumption. This is particularly important for battery-powered circuits. Unfortunately, oscillators often require quite a bit of current. We therefore propose this oscillator circuit that has a very low current consumption (about 3 µA). The circuit is powered from a type LM334Z current source. The current has been set with R4 to about 3 µA. This is sufficient to power IC1 and the oscillator circuit around X1. The oscillator generates, with the aid of a cheap watch crystal and a few surrounding parts, a signal that is subsequently applied to the divider in the 4060 and results in a frequency of 2 Hz at pin 3 (output Q13). The level of the output pulses is a lot lower than the nominal 5-V power supply voltage (IC1 is after all powered from a current source with very low current). That is why the signal on pin 3 of IC1 is amplified and inverted by T1. IC3a finally turns it into a proper square wave with acceptably steep edges.

Thrifty 2-Hz Clock circuit schematic
Continue Reading..

Saturday, September 28, 2013

Temporarily Silencing A Smoke Detector

It provides a means of temporarily silencing a battery-powered smoke detector after you’ve burnt the toast, scorched the baked beans – or whatever! Unlike the earlier design, this more sophisticated version does not cause strange chirps and whistles to emanate from the smoke detector towards the end of the silenced period. It also flashes a LED and produces a series of short, unobtrusive tones from its inbuilt buzzer while it is active. A separate 9V (or 6V) battery is required to power the circuit, which is mounted remotely from the smoke alarm. Connection to the alarm is made via a 3-core data cable terminated in a 3.5mm stereo plug, while a matching switched socket is fitted to the alarm’s casing. In addition to the socket, only three other components are installed inside the smoke alarm.

These are Mosfet Q3, its 100W gate resistor and 15V zener diode ZD1. These parts can all be mounted on a small section of prototyping board or soldered point to point from the socket terminals. The Mosfet is wired in series with the smoke alarm’s negative battery lead and acts as a switch. As shown, the contacts of the socket must be wired so that the Mosfet drain-source connections are shorted out when the plug is removed, thus allowing immediate restoration of the smoke alarm to normal operation. When the silencer circuit is inactive, the reed relay (RLY1) is off, so battery power is disconnected from the circuit. An exception to this is Q3’s 4.7kO gate pull-up resistor, which is powered directly from the battery. This holds the Mosfet switch on, powering the smoke alarm from its on-board 9V battery.

Temporarily silencing a smoke detectorNow consider what happens when the "silence" switch (S1) is pressed. This action applies battery power to the entire circuit through the switch contacts. At the same time, IC1 (which is wired as a monostable) is triggered by a brief pulse on its reset input (pin 2). This initiates the 555’s timing sequence, so its output (pin 3) immediately swings high, switching on Q1 and activating the relay. A second transistor (Q2) wired to IC1’s output also conducts, pulling Q3’s gate low and switching it off. As a result, the smoke alarm is disconnected from its 9V battery and all of the noise ceases instantly! When the relay is closed, an additional path exists from battery positive to the circuit’s power rail – so that when the switch is released, the circuit keeps running.

The circuit then continues to run for the duration of IC1’s timing period (over 8 minutes). The remaining two 555 timers (IC2 & IC3) are configured as astable multivibrators. IC2 is used exclusively to flash an indicator LED at a rate of about once per second. IC3 has a longer period, sounding a piezo buzzer briefly about once every 10.5 seconds. Use a 5V reed relay when the circuit is powered from a 6V battery and a 12V version when powered from 9V. Because of the high impedance and low leakage of the Mosfet’s gate, the silencer’s battery can be expected to last almost its shelf life – assuming that you don’t burn the toast too often!

Warning:
  1. This circuit must not be used with mains-connected smoke detectors
  2. Test your smoke detector and this silencer circuit regularly.
Continue Reading..

Friday, September 27, 2013

Low Voltage Cutout For 12V SLA Batteries

This simple circuit protects an SLA battery from over-discharge by disconnecting the load when the terminal voltage drops below a preset level. In operation, a sample of the battery voltage is derived from the 22kΩ resistor and 20kΩ trimpot divider. This is applied to the non-inverting input (pin 3) of IC1, where it is compared with a reference voltage on the inverting input (pin 2). When the sampled battery voltage falls below the reference voltage, IC1’s output (pin 1) swings towards ground, switching Mosfet Q2 off and disconnecting the load from the battery. The reference voltage is derived from a 4.7V zener diode (ZD1), which is connected to ground via the collector-emitter circuit of Q1 (ie, when Q1 is on).

Low-voltage cutout for 12V SLA batteries circuit schematic

However, when the op amp’s output is driven low, Q1 is switched off, causing the non-inverting input to rise towards the full battery voltage. This greatly reinforces the switching action, latching the circuit in the "off" state until the battery is recharged and the reset switch (S1) pressed. The Mosfet used for Q2 should be selected to suit the intended application. The circuit could also drive a relay simply by connecting the coil across the "load" terminals. As is usual practice, a diode should be connected across the relay coil to limit back-EMF spikes.
Continue Reading..

Thursday, September 26, 2013

Fuse Box BMW R1100S Diagram

Fuse Box BMW R1100S Diagram - Here are new post for Fuse Box BMW R1100S Diagram.

Fuse Box BMW R1100S Diagram



Fuse Box BMW R1100S Diagram
Fuse Box BMW R1100S Diagram

Fuse Panel Layout Diagram Parts: Instrument panel, horn, power socket, instrument panel, Fuel pump, Motronic, Heated handlebar grips, brake light , Rear light, parking light, number palte light, controller for fuel warning lamp or indicator damping.
Continue Reading..

Wednesday, September 25, 2013

Tiny Dew Sensor

Dew (condensed moisture) adversely affects the normal performance of sensitive electronic devices. A low-cost circuit described here can be used to switch off any gadget automatically in case of excessive humidity. At the heart of the circuit is an inexpensive (resistor type) dew sensor element. Although dew sensor elements are widely used in video cassette players and recorders, these may not be easily available in local market. However, the same can be procured from authorized service cent res of reputed companies. The author used the dew sensor for FUNAI VCP model No. V.I.P. 3000A (Part No: 6808-08-04, reference no. 336) in his prototype.

In practice, it is observed that all dew sensors available for video application possess the same electrical characteristics irrespective of their physical shape/size, and hence are interchangeable and can be used in this project. The circuit is basically a switching type circuit made with the help of a popular dual op-amp IC LM358N which is configured here as a comparator. (Note that only one half of the IC is used here.) Under normal conditions, resistance of the dew sensor is low (1 kilo-ohm or so) and thus the voltage at its non-inverting terminal (pin 3) is low compared to that at its inverting input (pin 2) terminal.


The corresponding output of the comparator (at pin 1) is accordingly low and thus nothing happens in the circuit. When humidity exceeds 80 per cent, the sensor resistance increases rapidly. As a result, the non-inverting pin becomes more positive than the inverting pin. This pushes up the output of IC1 to a high level. As a consequence, the LED inside the opto-coupler is energized. At the same time LED1 provides a visual indication. The opto-coupler can be suitably interfaced to any electronic device for switching purpose. Circuit comprising diode D1, resistors R8 and R6 and capacitor C1 forms a low-voltage, low-current power supply unit. This simple arrangement obviates the requirement for a bulky and expensive step-down transformer.
Continue Reading..

Tuesday, September 24, 2013

Dimmer Control Voltage Polarity Changer

Some older Strand dimmer units used a zero to -10V control signal, and the standard analogue control voltage is zero to +10V. This project allows the easy conversion from one standard to another. This is a very simple project, but may turn out to be a lifesaver for small theatre groups and the like. It has come to my attention that there are still a great many old Strand dimmers very much in use. The problem is that they are just too reliable, and wont go away ... but, they use a zero to -10V control signal, so are incompatible with the dimmer unit in these project pages, and with any new commercial analogue control console.

In addition, there are no doubt quite a few old lighting consoles that use this standard, which means that they cant drive modern dimmer packs. As it turns out, a simple opamp inverter will convert either standard to the other. This is shown in Figure 1.

Dimmer Control Voltage Polarity Changer circuit diagramFigure 1 - Dimmer Control Signal Inverter

There is really nothing to it. Use as many circuits as needed, and a simple power supply (such as that in Project 05) will drive as many of these inverters as are likely to be required in any lighting setup. The above circuit has two channels, and may be simply repeated as many times as you need to get the required number of channels. The 100 ohm resistors on each output are there to prevent the opamps from oscillating when supplying a capacitive load (such as a coax cable).

With an input of zero volts, the output will also be at zero volts. As the input increases (or decreases in the case of the -10V control) the output will change by exactly the same value, but in the opposite direction. Wiring is not critical, the 1458 opamps specified are very cheap (but more than capable of doing the job), and they can be built very simply on Veroboard or similar. Supplies should be bypassed to common (ground) with 10uF electrolytic caps.
Continue Reading..

Monday, September 23, 2013

Download 2012 GMC Terrain Owners Manual

2012 GMC Terrain owner Manual
This 2012 GMC Terrain owner Manual describes features that may or may not be on your specific vehicle either because they are options that you did not purchase or due to changes subsequent to the printing of this owner manual. Please refer to the purchase documentation relating to your specific vehicle to confirm each of the features found on your vehicle.

For vehicles first sold in Canada, substitute the name “General Motors of Canada Limited” for GMC Motor Division wherever it appears in this manual. Download 2012 GMC Terrain Owners Manual
Continue Reading..

Sunday, September 22, 2013

Non Contact Power Monitor circuit

Here is a simple non-contact AC power monitor for home appliances and laboratory equipment that should remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to the equipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables the oscillator when mains power is available. In the standby mode, the base of T1 picks up 50Hz mains hum during the positive half cycles of AC and T1 conducts.

Circuit diagram:

    Non-Contact Power Monitor circuit diagram

Non-Contact Power Monitor circuit diagram  

This provides base current to T2 and it also conducts, pulling the collector to ground potential. As the collectors of T1 and T2 are connected to pin 2 of NAND gate N1 of the oscillator, the oscillator gets disabled when the transistors conduct. Capacitor C1 prevents rise of the collector voltage of T2 again during the negative half cycles. When the power fails, the electrical field around the equipment’s wiring ceases and T1 and T2 turn off. Capacitor C1 starts charging via R1 and preset VR and when it gets sufficiently charged, the oscillator is enabled and the piezobuzzer produces a shrill tone. Resistor R1 protects T2 from short circuit if VR is adjusted to zero resistance.

The circuit can be easily assembled on a perforated/breadboard. Use a small plastic case to enclose the circuit and a telescopic antenna as aerial. A 9V battery can be used to power the circuit. Since the circuit draws only a few microamperes current in the standby mode, the battery will last several months. After assembling the circuit, take the aerial near the mains cable and adjust VR until the alarm stops to indicate the standby mode. The circuit can be placed on the equipment to be monitored close to the mains cable.

Continue Reading..

Saturday, September 21, 2013

1979 Jeep CJ Electrical Wiring Diagram

1979 Jeep CJ Elecrical Wiring Diagram
The part of 1979 Jeep CJ Electrical Wiring Diagram: accessory feed, air conditioner compressor, anti diesel solenoid, back up lamps, manual transmission, battery, boy, brake, cogar lighter, capacitor, chassis, marker & reflector, module assembly, neutral safety switch, oil lamp gauge, oil pressure sender, panel lamp, parking brake, park & signal lamp, resistor heater blower moor, splice, coil 6 cylinder, dimmer switch, distributor, electric choke, fuel gauges, fuel sender, ground fan lamp feed, headlamp, heater motor, ignition switch, horn relay, kick down, starting motor, stop lamp, tail & stop lamp, temperature gauge, temperature sender, windshield wiper, washer.
Continue Reading..

Friday, September 20, 2013

2003 Chevrolte Monte Carlo 3400 Wiring Diagram

2003 Chevrolet Monte Carlo 3400 Wiring Diagram


The Part of 1957-58 Dodge 4-Way Power Seat Wiring Diagram: compressor control, power
distribution, schematics, battery, ignition voltage, junction block, refrigerant pressure sensor, ctrl module, body ctrl module, compressor cluth, instrument panel lamp, fuse supply voltage,
Continue Reading..

Wednesday, September 11, 2013

Simpled Solar Powered Lithium Ion Battery Charger Circuit

The circuit below feeds a controlled current and voltage to a 3.6v lithium ion battery. The current is limited to 300ma and the voltage is limited to 4.2 volts. The circuit uses a LTC1734 IC from Linear Technology. No diode is needed between the circuit and a 6 volt solar panel. Some very nice 6 volt solar panels are available from www.plastecs.comTheir SP6-200-12 cranks out about 1 watt while the SP6-300-12 can produce about 2 watts. Assuming a 6 hour sunlit day, the 2 watt panel will pump about 1.8 amp-hours into a battery.


Solar Powered Lithium Ion Battery Charger Circuit
Continue Reading..

Tuesday, September 10, 2013

Current Controlled Boost LED Driver and Black Soldermasks

The MAX16834 is a neat little chip (its not the only one, there are plenty of others out there) that allows high efficiency designs for LED string driving. It provides a platform for a Buck or Boost converter design, as well as brightness adjustment via analog/PWM input pins, as well as a fault output (in case of open/short circuits for example) and also diverse other functionalities that can be quite useful.


Continue Reading..

Monday, September 9, 2013

Now Oyster Releases the First True Netflix for E books App

Now Oyster Releases the First True Netflix-for-E-books App

Now Oyster Releases the First True Netflix-for-E-books App. Netflix and Spotify have built multi-billion dollar enterprises by offering subscription services for film and music, respectively, but no company has actually made this form work for digital publications. Now, Oyster has disclosed its first try to change that.

Oyster, a New York-based startup, made headlines late last year when it broadcast lifting $3 million from Founders finance to construct out a service that would offer "unlimited access" to e-books. On Thursday, the startup commenced its e-reading app for iPhone, which is accessible on a first-come, first-served invitation-only cornerstone for now.

With the iPhone app, users get access to more than 100,000 ebooks from hundreds of publishers including Houghton Mifflin Harcourt, Melville House and one of the "big five" announcing houses, HarperCollins. Oyster will ascribe users $9.95 a month to read as numerous e-books as they like.

"People love accessing things when they desire it with one price," Eric Stromberg, co-founder of Oyster, said in an interview with Mashable. although, he believes a couple of obstacles have held back most startups from endeavouring to do the lone cost subscription form with e-books: "Any company that does this desires to be actually good at technology, at merchandise and on the joint venture side of things, and construction a centre area of know-how in each of those."

Another new ebook startup, is also trying to make the digital publication subscription notion work, but with a very distinct charge form. Rather than charge on flat monthly rate for unlimited reads, eReatah offers three tiered charges extending from $16.99 a month for two reads to $33.50 for four reads a month.

While the tiered pricing form could verify to be a better deal for publishers and authors, Stromberg states his group endeavoured to discover from living digital subscription services and put simultaneously a income model that "really places the rightsholders interest first and makes sense over decades." That said, the group is somewhat open to other charge structures in the future. "If we can provide a large experience kind of in a freemium form, well work in the direction of that," said Willem Van Lancker, one of the three co-founders.

The novelty of the subscription model for ebooks almost overshadows some of the more subtle but important changes Oyster is trying to make to the e-reading know-how. Like Netflix and Spotify, Oyster doesnt just provide easier get access to to content, but furthermore aspires to help users discover and share content. The publications are coordinated into genres similar to Netflix and every client has a social profile in the app and can pursue the reading undertaking of other users theyre connected to. There are furthermore constructed in choices to share books to Facebook, Twitter and even Instagram.

after that, Oyster made the interesting alternative to focus on the smartphone reading experience first, rather than tablets, where one might assume most persons do their long reading. The reasoning, according to the founders, is easy: many more people carry round smartphones than tablets. To make it work, though, Oysters group rethought the e-reading design: Users scroll through the text from peak to bottom rather than right to left, and they have more customizability over font kind and dimensions.

The two large-scale matters for Oyster are of course cost and selection. Oysters 100,000 books encompasses a pleasant variety of classics and up to date titles, but at launch its lacking numerous bestsellers and brand new releases. For the casual client, giving $120 a year for a service like this makes the most sense if you dont have to pay much more on top to read other issues not available to rent. In my own know-how, many of the publications I sought for — from well-known authors like Jonathan Lethem, George Saunders and Anthony Swofford — were unavailable. That may change if the service gets more traction amidst users and thus expanded leverage amidst publishers.

At $9.95 a month, Oyster is slightly more costly than Netflixs streaming-only option. That is a better worth proposition in the sense that you need only lease one ebook a month to at smallest shatter even, while you would need to watch multiple movies or display seasons a month on Netflix to come out ahead of usual rental charges in bricks-and-mortar video stores. Unfortunately, a Pew survey from last year discovered that just 27% of Americans read the matching of one or more publications per month — digital or physical — which proposes the $120/year could be seen as steep cost to pay for many.

For better or worse, the success or malfunction of Oyster may assist as the ultimate litmus check for whether digital apparatus boost the consumption of publications — in the way that they might with movies — or undermine it.

"You glimpse all the times someone says Im really enjoying shattering awful, its on Netflix, you have no apologise not to go at smallest give it a shot. We seem that same way with books," Stromberg says. With an get get access to to form, he states, "You spend less time conceiving about making a buy, less time conceiving about if you should read this publication and actually just start reading it. Thats ultimately the way youll be adept to notify you like it."
Continue Reading..

Wednesday, June 12, 2013

NiCd charger circuits

A simple NiCd charger can be built using ‘junk box’ components and an inexpensive LM317 or 78xx voltage regulator. Using a current limiter composed of R3 and a transistor, it can charge as many cells as desired until a ‘fully charged’ voltage determined by the voltage regulator is reached, and it indicates whether it is charging or has reached the fully charged state. If the storage capacitor (C1) is omitted, pulsed charging takes place. In this mode, a higher charging current can be used, with all of the control characteristics remaining the same. The operation of the circuit is quite simple. If the cells are not fully charged, a charging current flows freely from the voltage regulator, although it is limited by resistor R3 and transistor T1.

The limit is set by the formula Imax ≈ (0.6 V) ÷ R3 For Imax = 200 mA, this yields R3 = 3 Ω. The LED is on if current limiting is active, which also means that the cells are not yet fully charged. The potential on the reference lead of the voltage regulator is raised by approximately 2.9 V due to the voltage across the LED. This leads to a requirement for a certain minimum number of cells. For an LM317, the voltage between the reference lead and the output is 1.25 V, which means at least three cells must be charged (3 × 1.45 V > 2.9 V + 1.25 V). For a 78xx with a voltage drop of around 3 V (plus 2.9 V), the minimum number is four cells.

Circuit diagram.


When the cells are almost fully charged, the current gradually drops, so the current limiter becomes inactive and the LED goes out. In this state, the voltage on the reference lead of the regulator depends only on voltage divider R1/R2. For a 7805 regulator, the value of R2 is selected such that the current through it is 6 mA. Together with the current through the regulator (around 4 mA), this yields a current of around 10 mA through R1. If the voltage across R1 is 4 V (9 V – 5 V), this yields a value of 390 Ω. The end-of-charge voltage can thus be set to approximately 8.9 V. As the current through the regulator depends on the device manufacturer and the load, the value of R1 must be adjusted as necessary. The value of the storage capacitor must be matched to the selected charging current. As already mentioned, it can also be omitted for pulse charging.
Continue Reading..