Top Circuits Page 200
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To this small FM transmitter to change the mic for an audio jack so I can plug it into my mp3 player to listen to songs on my car audio. I looked at some of the transmitters on this site, but I think I`m going to go with this one, as I find it simple, and....
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The so-called regenerative effect of a 4-quadrant inverter. Yup you will need to dissipate that power somewhere. In big industrial drives this gets re-inverted onto the national grib, but hear I would suggest a braking cct. For low-power stuff (1W-5W) they....
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After installing in the car (Not running but with it in reverse and with emergency brake on) it also worked good! The when I started the car and backed out of the garage the beeping frequency became very eratic as I tapped the brake or turned the steerin..
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A very simple circuit for FM receiver, no IC required, and only a single transistor. I`m not sure whether this transistor works or not, I`m going to try this out. Have you guys seen this before It is a regenerative or super-regenerative simple radio....
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One of the critical components is a pwm speed controller, so that i can finely adjust my speed rather than just having an "on" mode that runs balls to the wall. That way may be fun for a little while but I value my life. lol PWM - I bought a basic stamp....
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You need to wire 8 Max6675 ics to a microcontroller. You can parallel all the clock inputs. The NCS lines of numbers 1 and 2, 3 and 4 etc can be connected together. The SO lines of all the odd numbered Max6675 can be connected together, as can the even ones.....
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The problem is when i connect the 8051 to the encoder the data send is not received at the receiver but as soon as the 8051 connections are removed the transmisison works perfectly. thus manually the RF communication works perfectly i. e the 8 bit data which....
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A GPS tracker demonstration program with data logging capacity. It uses BasicStamp 2P (also you can use PIC chip) to interface with a GPS Module, JP Module and 16x2 LCD display. Sample code used is standard PBasic 2. 5 ( It can be changed to PicBasic or....
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By looking at the layout of the PC board, decided to insert a stereo 3mm canceling type jack (5 pin) at the volume control chip inputs, and mounted it on the front panel. Did not find such type of jack in my parts bins, and canibalized one out of a old PC....
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The objective is to make a small light that is activated by motion and will remain on for 20 seconds and then deactivate. i. e. you pick up the light it illuminates youput it back down and it remains on for 20 seconds then turns itself off. until it is....
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This is a 9V DC power source, to a 555 timer to get a square wave. Then fed through a Half-Wave Series Multiplier (Villard Cascade) to get a high voltage DC output. Ideally I want to be able to send a single pulse at 5V pulse from a micro-controller to the....
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Used a 12V motorcylce Battery and an ignition coil of a car. A microcontroller produces some pulses to the base of a 2N3055 transistor. 2N3055 turn on an off the primary of the coil and the desirable sound is produced between the probe and the surface. I....
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Build a circuit that will flash 5 pairs of LEDs at variable rates. To do this I designed a circuit using 5 NE555 timers. To control the variable flash rate I want to use trim pots. I am having a hard time figuring out where to lay out the trim pot and what....
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Some simple 555 and flip flop circuits to add electronic lighting effects to "modernize" the games. I`m collecting quite a few for different aspects of the game - i. e. idle, flipper shot, flowers open, winning shot etc. I have a few hundred LED`s, 20....
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Another way other than magnetic reed switches for the alarm trip switch. The circuit needs the switch to be normally closed / held open (when the door is shut. ). I was looking to use a normally closed momentary push button. Another thought was trying to....
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Power a rs232-TTL converter circuit using the serial port so i dont have to have an external power supply to do the job. I read somewhere that the DTS, RTS and TD pins are able to do this. As I am already using the TD pin to send out data, is there any other....
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At 9 volts the maximum stalled current of the motor types I`m going to use will be 700 mA. Since I`m not real experienced with this I want to check that I`m choosing good mosfets, I`m pretty clear on the rating, they say what current and voltage they can....
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A circuit to turn on/off a couple of big AC solenoid valves and a couple of 1ph ac motors. my line v is 132VAC and the solenoids measure 1A and the motors measure 13A and 27A once running. does anyone know how to do this with triacs they are much cheaper....
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Look at the left side of the circuit (sensing coil and op-amp). When I wired mine the way shown in the schematic, it wouldn`t pick up anything. I didn`t have a 1mH radial inductor handy, so I fashioned my own using 30ga enamel wire and a round core (100....
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Build a device to determine the depth of the flocculent layer in a lake. The flocculent layer is a mud layer that has a similar consistency of water. It is pretty difficult to determine its depth accurately from the surface. I have a paper that describes a....
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If you replace the resistor/transistor with an n-ch power mosfet, and replace the relay/prot diode with a light bulb, you`ll have a simpler circuit that replicates the circuit you posted (assuming it drives a light bulb with one end connected to +12). If the....
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Connected 0. 1uf cap and 500uf electrolytic cap to transmitter and the same to receiver. The result was it still does not work. I tried to add just diodes but it did not help either. when u say it doesent work-what is happening when the ir is recieved by the....
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A nice schematic for an lm3915 VU meter. I have attempted to create a band pass filter in order to only input part of the audio frequency spectrum into the VU meter circuit, this is becuase I plan to have 5 of these circuits to make a spectrum analyser or....
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Modify a zapper circuit (like the Hulda Clark Zapper) to get two differente frequencies. One switch to make the pulse to 15Hz and the other to 30. 000Hz. The nominal frequency for that circuit is 35kHz (35, 000 Hz), not 30 Hz. You can cut the frequency in....
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An error amplifier is formed from Tr1 and Tr2, wired as a differential amplifier (often called a long-tailed pair - look at those collector leads). One input of this diff. amp is taken from the zener diode which provides a stable 4. 7 volts, the other diff.....
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At first glance this circuit looks fairly complex, but when broken down, can be divided into high pass and low pass filter sections followed by a summing amplifier with a gain of around 20 times. Supply rail voltage is +/- 9V DC. The controls may also be....
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Under dry conditions, the transistor will have no bias current and be fully off. However as the probes get wet the transistor will conduct and sounding the alarm. An On/Off switch is provided and remember to use a non-reactive metal for th..
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for example i dont get the way the demodulation is done or the modulation itself an so on please is someone able to understand this circuit could you give me a hand..
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This was used on a Linear actuator for a variable geometry turbine used for more power to compensate for all the armor they started putting on HumVees. I forget the current rating, where ARE my old design notebooks ! The four darlingtons are the driver....
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The AQV20 series should be fine to drive an A. C. relay coil if the de-energizing back EMF from the relay coil does not exceed 600 v rating. It is diode in series with a conducting MOSFET. Might want to add two back to back zener surge suppressors across....
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Designing a true constant-current AA NiMH charger, and want to select a power supply that will be just right. I want a high enough voltage to that the CC transistor doesn`t saturate, yet low enough voltage to reduce the power dissipation in the transistor. I....
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The electret microphone has a current of 200uA which changes by +- 3 uA depending on sound waves. This sets the voltage across R1 to 2V and the voltage across the mic to 4 volts. As the sound hits the mic the current through R1 increases slightly reducing....
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Control a car toy. The toy car is controlled via a controller that is connected to it via a wire, so it`s not radio controlled. I would like to use relays to control toy via parallel port. I think there are many relay types and models, and I would like to....
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It looks as if they are highly prone to harmonics meaning in this case, that if the resonator is 455KHz, it will also allow 910Hz and 1820KHz and 3. 640MHz which seems to be dominant and on up. But the frequency around 3MHz seems to be prevalent and one or....
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Make two telephones ring onstage. This involves sending a signal down a line to the phones. I was hoping to find an old telephone exchange system, but no luck yet. I have found a few ideas for circuits, but would ideally like to make a ringer output that is....
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yeah, you really need some current limiting. i use open frame linear supplies for charging batteries, and set the current limit at the recommended charging current of the battery (foldback current limiting is very useful), but then again, i have a few of....
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I`m afraid the circuit you have there is nowhere near correct. For a start, there is no DC path to the transistor base, so no base bias current is available. Q1 collector and emitter are connected directly to the battery with no intervening impedance, so the....
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What you have sounds like something from this type family of sensors. Not really a good choice of sensor for use with a PIC and actually a pretty low end sensor as to accuracy. There is a little more information located here. Personally I don`t see it as a....
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Im pursuing a homemade photography LED array. Ideally, the LED array will be 6 series 5 parallel. (24 volts @ 1000mA per row). Each LED row is a different wavelength, together they make up the whole spectrum. Each LED row I want to have adjustable so you can....
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and I think I understand what`s going on. the induction coil senses the magnetic field flux around when the phone calls, boosts the signal, and pulses the LED. These types of circuits were meant to have the phone sitting on the pickup coil. The emf from the....
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I got frustrated and decided to hook it up to a 15v supply and jump R3 with a clip-on soldering heat sink. 555`s smell great when you fry`em. I have about 9 more tries before I run out of parts, but for now I will seek help in the forums and stick to the....
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I want to know if I can connect 2 dimmers in series to control more preciselly the light of a bulb. I want to get a medium/high precission of light emission, for a school project. I wonder if you can get a manufacturer to lend you a DC power supply in....
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Yesterday I was triyng to read the infrared impulses from my electricity meter. The phototransistor I`m using, can see the IR from all the remotes in the house. but doesn`t read the blink from the electricity meter. I can see the IR blink of the meter with....
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Hey everyone. I am building a keypad lock for a project using a PIC and one of those passive keypa with 8 pins, 4 input 4 output. Each of the pins corresponds to a row of numbers on the 4 by 4 keypad, and the 4 output pins correspond to the numbers in that....
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Hello All Experts, i m in need of Transistor Ignition to replace point breaker from my motorcycle. i read many many articles in internet google and almost all forums but did not yet found working and simples smallest circuit yet. and which i found they dont....
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I would like to learn if this circuit will invert the input signal or not. The opamp is single supplied, and supply voltage is 5V. The input signal is varying between 0V and 5V. What happens the the output voltage if the signal is inverted I think, if you....
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try another op amp. I could be changes in the input bias current that is causing a strange voltage drop across the 10k resistors. The LM358 is not really a high quality op amp it`s the diodes in the feedback loop. that`s a poor choice of limiter for a sine....
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I`m working on a project with a PIC to communicate with the Raymarine SeaTalk bus. The link below is the part of the schematic diagram of a Raymarine instrument. The logic chip is connected to the TX and RX connections on the right, and the SeaTalk signals....
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Hi, this is my first post here. For the past few days I`ve been building a tape delay unit. Mechanically, it works well, but I still need to design a circuit to link all the parts together. This is, however, beyond my current level of ability, and I was....
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i need to control it with a ordinary pic. could someone please explain me how do i do it. im using it to control lego light sensor ..
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I`ve tried to make drivers for my H-bridge circuit using complimentary emmiters but the square wave outputs runat a constant 25v instead of +-10v square wave The image is a bit hard to read but it looks like your mosfets` gates and sources are wire together....
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The astable multivibrator I found in wikipedia and also my college material are the same, which is on the left hand side of the picture. While for the schematic at the right hand side, I found it from the example of LTSpice. I would say because it`s drawn....
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About all that can be said about top octave generators is that they were cute and cheap, compared to other methods of tone generation. Trouble is, they were nearly perfect and to use one resulted in chords that were very flat-sounding and on organs, stops....
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i had a problem while designing a circuit in which BT 136TRIAC has to be triggered from a half rectified current of 30 mA at about 6V. Its not getting triggered. Even for this supply my trigger circuit is consuming power as the 4. 7k 10W resistor is getting....
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I would like to convert a TTL square wave into sine wave. The frequency range of the square wave is: 4Hz-60Hz (yes its those evil low frequency experiments that I plant to take over the world with One approach is to filter the square wave with a high order....
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Does anyone know what circuit i can use to make a dc motor randomly move backward and forward, stop for a period of time and then start again Any help and ideas will be much apreciated. Google and read about how to wire up PICs. In the simplest sense, it....
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Any idea where can I get the schematics for the dome light dimmer to be used in car. Which means that when I open the door, the light will light up and when closed, the light will slower dim and off. Thank you for the reply, how would I connect the circuit....
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I am trying to design a digitally controlled analogue oscillator. The idea is that a control voltage is generated by the a microcontroller (Arduino) which is used via the 2 op amps, resistor and capacitor network which forms a integrator circuit. The....
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I have a 10 light LED bargraph, I want to make the LED`s light one after the other until all the LED`s are lit, and then have the circuit cycle back down until all the LED`s are off again. A simpler (analog) way is a LM3914 - Dot/Bar Display Driver operating....
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I`m making a small DC tesla coil with a rotating spark gap. The motor controlling the RSG draws about 3. 8 amps of current at full load, and the 555 control circuit and amp draws about 4 amps. Would it be best to run the motor and 555 circuit parallel from....
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I`m doing this lab BCD COUNTER and 7 SEGMENT DISPLAY and im using CD4510BMS presettable BCD Up/Down Counter. I was able to do the counting from 00-99 but i can`t figure out the counting from 32-84. Do i need another gate for this operation Okay, sorry about....
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problem is my MOSFET gets realy hot. due to the circuit is using half bridge and no mosfet driver. I cannot get the tc4429 ic where i live. any other ideas how i can stop my MOSFET over heating, or maybe how to conect another mosfet driver. Probably wouldn`t....
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Here is a simple and powerful LED based night lamp circuit that can be operated directly from the 230V mains supply. The are total 24 white LEDs used and the lamp produces an output of around 15W. The resistance R1 and capacitor C1 provides necessary current....
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I`ve built a 555 based oscillator to drive ir led at 38khz. I`ve got the circuit wired up and I`ve used my meter on the duty setting to read that it is indeed generated a 38khz signal. I`ve also wired up a modulated IR receiver, the one from radio shack set....
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* This meter looked like it works well: YouTube - IndikG tor vybuzenG s LM3915 but the schematic is quite different. Google Translate If I followed that schematic, do you think everything would still work You should use a peak detector circuit at the input....
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Might be a stupid quiestion but as 240vac-12vac transformers are readily available (and are roughly the same scale) could i use one of these in the circuit instead If the specific transformer mentioned in the schematic is not available to you, any....
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hi every one im not in the line to electronics so please can any one make a diagram for me that how i change this circuit so that it will dial a number using speed dial and also beeps a siren when triggerd and i also add some vibration sensors as siren....
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Well i posted a similar circuit in another topic but a lot has changed in the design. So here is a brief story of what i am doing, actually i am in a project where i have to design a circuit which can be used to trigger solenoid valves for the airbags in the....
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I usually use an NPN Bipolar transistor to do the relay switching, mainly because my relays are 12v coil rated, but it also keeps everything nice and seperated. and yes i add a diode. with no problem. ( do I or did I need to drive it with a transistor ) but....
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I am a beginner/hobyist and would like to learn more about Microcontrollers. All I want to do is receive an output on an LCD when pressing a button on the keypad. ..
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I`m designing a circuit to drive a 4x7 segment display using a PIC. I`ve done this in the past without any drama. I would just use four pins to control each of the four digits (one each). I`d switch one digit on, wait a bit, turn it off, then switch the....
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there are countless applications for use of this hardware. Touch pad, proximity sensors, readout of capacitive sensors, extreme precision capacitance measurement, ultra small capacitance change detection, soil moisture, skin moisture measurement are just....
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hi i have been working on this code for a while now and i have come to a complete dead end. the following code takes midi data on the rx pin of the usart, saves the 3 bytes of data in the cblock, tests the first byte to see if it is a midi on message....
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A friend of mine bought a fairly new (only a couple of years old) Fender 60W combo off a guy he knew for £5. The original owner had taken it to three different repair shops, and been told it wasn`t worth repairing. I told my mate it couldn`t be much, and....
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You might find yourself needing a low power H bridge for driving a motor like I once did. The 555 IC can drive a load up to 200mA, source or sink, which might make is usable as a driver, if one can control the output as desired. Although it is an unusual use....
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I have recently stumbled upon some LED strip at my local electronics shop and decided to give them a try. I bought some which I used to replace the spot lights in the kitchen. It is cold white, which is surprisingly good, especially for night time....
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Amplifier circuit for electret microphones (condenser microphones). Amplifier the audio signals picked up by the electret microphone, using 741 op-amp and a 2N2222 transistor....
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Modular power supplies enjoy disproportional growth. Personnel limitations of development engineers for discrete solutions increase costs, while readily available modules feature lower prices. Aspects such as higher efficiency, easier certification and the....
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I n this circuit, the alarm will be switched on under the following four different conditions: 1. When light falls on LDR1 (at the entry to the premises). 2. When light falling on LDR2 is obstructed. 3. When door switches are opened or a wire is broken. 4.....
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The circuit uses the very popular Sharp IR module (Vishay module can also be used). The pin nos. shown in the circuit are for the Sharp & VIshay modules. For other modules please refer to their respective datasheets. The receiver consists of a 555 timer IC....
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This is a simple but effective alarm circuit which can reset its self after a time that you select. it has normally open and normally closed triggers which make this circuit very practical. This alarm has normally open and normally closed triggers. It`s on a....
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It has to placed making an angle of about 30 - 45 degrees to the ground. This makes the rain water to flow through it to the ground and prevents the alarm from going on due to the stored water on the sensor. The metal used to make the sensor has to be....
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The add-on circuit presented here is useful for stereo systems. This circuit has provision for connecting stereo outputs from four different sources/channels as inputs and only one of them is selected/connected to the output at any one time. When power....
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Ensure that the 12V(yellow) wire is connected to the right of the D-connector(as seen from behind, i. e the connector holes away from you with the curved portion of the connector upwards) Disclaimer: All the information present on this site are for personal....
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Many a times one needs an extra telephone ringer in an ad joining room to know if there is an incoming call. For example, if the telephone is installed in the drawing room you may need an extra ringer in the bedroom. All that needs to be done is to connect....
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A battery is a vital element of any battery-backed system. In many cases the battery is more expensive than the system it is backing up. Hence we need to adopt all practical measures to conserve battery life. As per manufacturer`s data sheets, a 12V....
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Here is a simple technique for measuring frequencies over quite a wide frequency range and with acceptable accuracy limits using a PC. It follows the basic technique of measuring low frequencies, i. e. at low frequency, period is measured for a complete wave....
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This jam circuit can be used in quiz contests wherein any par- ticipant who presses his button (switch) before the other contestants, gets the first chance to answer a question. The circuit given here permits up to eight contestants with each one allotted a....