Top Circuits Page 240
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Boosters are not buffers! While it is possible to make a booster that also provides a buffering action, the vast majority of the boosters commercially available ready-made or kits, do not have the proper design to be buffers. A buffer should have a high....
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There are only 4 parts to the circuit, including the indicator LED. There is a hand-wound coil, a 1k resistor, a 2N4401 transistor and the LED. I quickly threw this together by just wiring the component leads together and it worked right away. The coil is....
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The wah will work before the amplifier but sounds very low in volume and it sounds scratchy when the wah is rocked back and forth. The wah is fine without the buffer. In front of a fuzz face, with the fuzz face on, no sound passes Bizarre indeed. I`m going....
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This is the complete schematic for the circuit that is contained on the AMZ Multi-Purpose PC Board. None of the example circuits will utilize every part that has been positioned on the board. Extra parts have been included to add flexibility and options to....
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The classic Rangemaster is thought to have been the source of some of the best tones in rock guitar, from Clapton`s Beano sound to some of Brian May`s singing sustain tones. While the effect is a simple one-transistor booster, locating a good quality....
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This project, based on an article published in the February 2008 edition of Radcom (the magazine of the Radio Society of Great Britain) is for a meter with a 50 ohm input impedance for measuring very small RF powers. Many RF power meters become inaccurate at....
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Colpitts oscillators are somewhat similar to the shunt fed Hartley circuit except the Colpitts oscillator, instead of having a tapped inductor, utilises two series capacitors in its LC circuit. With the Colpitts oscillator the connection between these two....
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Hartley oscillator are inductively coupled, variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor. This arrangement simplifies the....
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An AM receiver relies upon the original carrier signal (station frequency) having been amplitude modulated. This means the original amplitude (strength) varies at an audio rate. Looking at figure 1 we can see an unmodulated carrier signal as it might be seen....
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FM wireless Mike is a small electronic project based on a radio transmitter. It is a wonderful idea to make a wacky talky through which you can talk to your friend, next door. Just speak or play into the microphone and you ’ll broadcast to an FM receiver at....
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This project is a wonderful idea of saving electric bill when you are using a heavy wattage bulbs. With miniature components and extreme care you can build a low power lamp dimmer right into the socket. Instead of a relativity expensive trigger diode, an....
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At the point Vp the Emitter triggers and TURN the ujt ON, until this point ; the emitter is isolated(doesnt conduct) from the transistor so no Current Conduction occurs between Base1 and Base2...
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The LDR is a variable resistor whose resistance decreases with increase in light intensity. When the light falling on an LDR has normal intensity, its Resistance is large enough and the voltage across R is insufficient to trigger the SCR. However, when light....
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This circuit have an advantage over ordinary CONTINUITY testing Device, usually we are using multimeter to check the continuity of a circuit. It is not suitable to check the continuity of a circuit with high Impedence or resistance like Transformer,....
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Here is the circuit diagram for simple door bell, you can assemble this circuit inside your room or home where as keep the switch outside your home or room that is easily noticable by the visitors. The working of this circuit is almost similar to my previous....
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The timer IC(NE555) is wired as an ASTABLE MULTIVIBRATOR in this circuit. It will generate Alternating non sinusoidal output wave form at the instant we giving supply Voltage(12V). Thus primarily we generated Alternating Voltage from direct Current....
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Assume initially, that there is a voltage Vc on capacitor C1 larger than Vbb-Vg. Where Vg is the cut in base to Emitter voltage and g represent Gamma. Hence the transistor is off and the capacitor C1 discharges exponentially towards ground with a time....
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This circuit is also called as Free Running Oscillator. Because, it doesn`t requires any trigger pulse to get active. Consider the instant at which Vc=+Vsat. Now the capacitor charges exponentially towards +Vsat through R. Automatically, Vd increases and....
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This circuit alarms whenever someone cross the Laser beam transmitted from a LASER. The output of IC TL071 goes high whenever their is no Light(Laser) Ray. This output voltage is further amplified by means of a NPN transistor Q2, which will drive the buzzer....
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The circuit remains in stable state until a triggering signal is applied to its input. After getting the triggering signal the output transit from stable to Quasi-stable state and return back after a time period. So a Single Pulse isgenerated for single....
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I am presenting you a 230V LED Driver circuit without transformer. Here i am using 5 led`s you can increase the count at your convineance. Due to the absence of Transformers we can reduce the cost and size of the circuit considerably. As we all know LED`s....
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This circuit is composed of a temperature sensor, amplifier, V/F converter, three digit binary coded decimal (BCD) counter, time base and seven segment led displays. In addition to the 9400 V/F converter, other ICs need for this project include the LM334....
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I am going to present you fabulous Electronic project, DEVICE CONTROL USING TIMER. By using this circuit you can turn ON an appliance at a desired time for a specific time interval. You can use this concept to control the operation of a furnace or central....
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I am presenting you a simple smoke sensing alarm circuit using 555 timer. By using this circuit you can detect smoke and it alarms when the air is contaminated. Let me introduce you the components used in it. This smoke detecting alarm is based directly on....
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The ultimate source of energy is Sun. it is possible to generate current from sunlight using solar panels. These panels convert light energy into electrical energy. A solar panel consisting of a number of solar cells, which will produce a small amount of....
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An Operational amplifier based sine wave generator circuit, it is basically a wein bridge oscillator. Because of its simplicity and stability, one of the most commonly used audio frequency oscillator is wein-bridge. The wein bridge oscillator in which the....
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A Simple Transistorized one Minute Delay Timer Circuit. It doesn`t include any complex or critical parts. You can use this circuit to generate a time delay of about one minute. That is, When you press the switch (Push button type is preferred) the LED turns....
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A Tv remote jammer circuit, using NE555 timer IC. By using this you can watch your favorite TV channel without any interruptions. Ie; No one can be able to change the channel by means of remote, if the circuit remains ON. The circuit is simple to make at....
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Ne555 is one of the most commonly used timer IC. It is a monolithic timing circuit that can produce accurate and highly stable time delays or oscillations. Like general purpose OP AMPs, it is very much reliable, easy to use and cheaper in cost. It has a....
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Every innovations starts from a simple day to day life problem like you watching IPL in TV and suddenly the current shuts off, fortunately you will find another way to watch the match via mobile network. Similarly, I too had faced a problem of frequent....
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This article helps you to make a Light Sensitive Morning Alarm circuit. The morning light is sensed by an LDR (Light Dependent Resistor) or Photoresistor and it triggers the alarming section. The circuit generates a melodious tone when light falls on it.....
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Attached are 3 captures from my L297/L298 board using the same motor at 500, 750 and 900 steps/sec on a 36v supply, wired bipolar parallel (coil resistance = 3. 2ohm). This shows the A-enable signal (blue) and the sense voltage (red). The sense voltage is....
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Tried to limit the number of wire jumpers in this board but things got a little tight since I was combining the microcontroller and motor driver in one board. It would have been a lot cleaner if I would have left the programming header off. The L298N is a....
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This is another project which fullfills a need. I once built a frequency counter using plain TTL chips. That was long before the CMOS HC versions, even before LS was available. It uses only 4 chips - 3 HC TTL`s and an Atmel At90S2313 microcontroller. It has....
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A simple function generator. Just to generate a certain frequency. While waiting for the AD9832 chip to arrive, I came up with a very simple version of the DDS synth, using just the 2313 and a resistor network. It`s controlled over RS232 from a small Windows....
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Low-Pass and High-Pass audio output signal filters. Additional Sound Source Low Pass filter and experimental original design puls-gate signal filter ("processor"), both of which have independent or linked together Voltage Control input option. The....
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The successive approximation Analog to Digital Converter(ADC) is probably the most common ADC. It requires few parts, and is simple to operate. Also, it always takes exactly the same amount of time to calculate the result. In a nutshell, it consists of a....
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This is yet another variation on the "parallel resistor" dummy load. [Go -here- for a discussion on dummy load theory]. This is another one I built during my infatuation with copper pipe. It`s suitable for QRP HF operation of 5-watts or less average power,....
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Simple modifications I`ve done on these rigs, to overcome some common shortcomings. Not all kits need these mods, but many do. Some overcomeminor inconveniences, and some potentially serious problems. If you have built one of these kits before, and....
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The Coupe to USB adaptor - AKA `microwidget` is an inline adaptor to allow a laptop user running Windows 2k or Windows XP (it is as yet untested with Vista but should work) to interrogate the ECU on the Fiat Coupe. With suitable software, the ECU can be....
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The clock is constructed on two boards; one carries the HT generator and the processor logic, the other the tubes. Thisallows a slightly more compact design that the previous effort, but didn`t save as much real estate as I`d hoped. The tubes are mounted on....
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The required output at the inverter is 220/230V @60Hz. Basically, let me say i need an inverted circuit diagram with an output power of 1000VA. While the first circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt....
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This web page describes the radio transmitter unit that flew aboard the Cirrus One rocket in April 2001. The intent of including the transmitter as payload was to: As the Cirrus One rocket was expected to achieve an altitude that would be well out of visual....
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Before I began building amateur rockets, I built and flew model rockets, starting in the summer of 1971. Looking for a greater challenge, the following year I decided to begin building my own rockets, entirely from scratch. Although my first rocket was a....
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This web page presents details regarding the design of a strain gage based load cell that can be used, in conjunction with an electronic data acquisition (DAQ) system, for static thrust measurement of a rocket motor. The load cell described here is meant to....
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I have one Meanwell LED driver of 27V, 2300mA on hand and will be running 2 strings of 6 LEDs in parallel. Should I follow the same circuit with same component value or should I need to change the value of the resistors to my configuration "The addition of a....
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I experienced faulty DS18B20 reads on my tank thermometers, probably due to my heatshrink/silicone waterproofing method. It gave me a chance to improve my code to make the controller more tolerant of bad reads, but my tank thermometers have now been replaced....
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The memory part of my Mark 2 system is extremely simple. There are two 32K SRAM chips (actually FRAM because I had them lying around, but there isn`t any significant difference in this application). These are selected with the logical OR of the MREQ signal....
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The basic requirement was for some sort of output display and some sort of alpha-numeric input. So the simplest solution I could think of was a UART, attached to something with a screen and keyboard running a serial terminal. I looked at using the PIC....
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The H-bridge is a circuit used in electronic control of high current devices, particularly where the device polarity may be reversed, e. g. DC motors. The name comes from the fact that the circuit typically looks like a letter "H". The circuit shown has four....
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The term amplifier as used in this article can mean either a circuit (or stage) using a single active device or a complete system such as a packaged audio hi-fi amplifier. An electronic amplifier is a device for increasing the power of a signal. It does this....
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A hydraulic or hydrostatic drive system or hydraulic power transmission is a drive or transmission system that uses hydraulic fluid under pressureto drive machinery. The term hydrostatic refers to the transfer of energy from flow and pressure, not from the....
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A multivibrator is an electronic circuit used to implement a variety of simple two-state systems such as oscillators, timers and flip-flops. The most common form is the astable or oscillating type, which generates a square wave - the high level of harmonics....
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To generate and maintain the EP, perilymphatic K+ enters fibrocytes (F) via Na+/K+-ATPase and Na-K-Cl cotransporter. Gap junction networks connect fibrocytes to strial basal (SB) and intermediate (SI) cells, allowing ions to enter the intrastrial space via....
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An illustration of the electronic impedances of a solid-state nanopore chip. (b) Simplified circuit schematic of the voltage-clamp current preamplifier. (c) Circuit design of the low-noise current source that substitutes for a feedback resistance (RF). (d)....
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Circuit schematic of the UDC containing only dispersive components. The two low-frequency series LC resonators (with LA=LB and CA=CB) are fed by two input semi-infinite transmission lines, A and B, and parametrically coupled to a third high-frequency series....
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This section contains details for providing a composite video output signal from the camera to drive an external monitor. The circuit described below, designed by Peter Smith, is a combined DC-restorer, switchable gamma corrector and video/sync mixer using a....
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To get the best from an NBTV signal it is important to use the full dynamic range of the signal with no crushing at black level or peak white. To check the linearity of a video path it is usual to use either a staircase or sawtooth test signal. The circuit....
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With the recent events at the Fukushima Dai-ichi nuclear power plant, I thought it would be pretty cool to build a Geiger Counter and hook it up to my NerdKit for interfacing with my computer. I`ve found this article which explains the building process....
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Control a fan using an LM34 temp sensor and a computer fan with model number : ASB0912L. I used a 2N7000 mosfet transistor as a switch. I want my fan to run at 35% duty cyle when the temperature is above 77 fahrenheit and to run at 0% duty cycle when....
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Read and write the raw data from an SD card using just a computer (no microprocessor) forgetting the FAT32. I would like to do this in basic C. I can look at the raw data with a program called winhex. Long run I want someone who is less computer savvy to run....
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The point being if it connects it`s good if it don`t it don`t, there`s no inbetween. If you got a solder joint it`s going to connect or it`s not going to connect, that`s it. 0. 25 to 4ohms come on really. Do they even make resistors that small to set it with....
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There are two major types of backlights for LCDs: LEDs, which stands for light emitting diode, or EL, which stands for electroluminescent. EL backlights tend to be more efficient and have more uniform lighting than LED ones, but they require some tricky....
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For this special Halloween project we built a spooky candy bowl that lights up when an unsuspecting trick-or-treater reaches in. While devices like these do exist, many of them use complicated proximity sensors to spring their trap. Here at NerdKits we enjoy....
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This project uses a magnetic reed switch, a NerdKit, and set of computer speakers to frighten unsuspecting visitors at the door. In covering constructing this project, we get a chance to go over some pretty neat engineering concepts: digital audio, data....
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Using the OBD-II (On Board Diagnostics) protocol, we can read live information from a car`s computer with our NerdKits microcontroller kit, as explained by our guest star, Elena T. , MIT class of 2011. This uses the port under your steering wheel to receive....
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We always like to use Halloween as a chance to show off neat homemade electronics to the general public. In this special Halloween video tutorial, we have recreated the idea behind a musical instrument called the theremin, and built one into a Halloween....
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Marx Generators are often used in pulsed power and high voltage applications to generate a high peak voltage pulse. The simplified theory behind them is that a number of capacitors are charged in parallel and then switches are closed to connect them in....
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build an interface board to connect some scientific equipment (for me, a pair of photovoltaic tubes) to a personal computer to acquire measurements results. Signal properties were following: two channels with a common ground, 1 second of acquisition time,....
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The circuit of the unit is fairly simple, but is a bit irksome to set up. The reason is that obtaining matched FETs is not easy, so I had to make sure that the circuit would work with off-the-shelf FETs. The phase shifter is a standard opamp circuit, and has....
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Each CdS cell acts as a variable resistor in a single variable phase-shift circuit and there are six such individual phase shifters arranged in series, each increasing the overall shift. The LED`s brightness is modulated by an oscillator (bottom section of....
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This simple circuit generates both white and pin noise. Transistor Q1 is used as a zener diode. The normal base-emitter junction is reverse-biased and goes into zener breakdown at about 7 to 8 volts. The zener noise current from Q G flows into the base of Q2....
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The heart of the circuit is IC2, a 50240 top-octave generator. That device uses a single input-frequency to generate all twelve notes of the musical scale. The input signal is provided by IC1, a 4001 quad 2-input NOR gate. Two sections of that IC are used to....
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The circuit consists of a white noise generator which only switches on with the high part of the square wave output from the clock circuit. The frequency of the clock is adjusted with the 10 pot and the output voltage of the clock is adjusted by the 100 k....
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I have made a major correction to the schematic as a result of getting a second board going. The manual sweep circuit should return to ground not vref. I also increased the feedback limiting resistor from 100K to 270K. This area of the circuit might bear....
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Unfortunatately this only provides 1. 8v signals and still needs a converter to interface to the 3. 3v signals most raw LCD use. The main components is the TFP101A. I got mine as a free sample from TI. Also visible in this picture is the fact that only the....
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This circuit, which was developed to monitor the traffic of bumblebees in and out of the hive, differentiates a-to-b motion from b-to-b motion. When used with an optical decoder, the circuit distinguishes clockwise from counterclockwise rotation and provides....
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This circuit consists of an amplifier and video detector with a second subcarrier detector for synch recovery purposes. A pulse-former circuit modulates the gain of the main channel increasing it during synch intervals...
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The zener provides a constant voltage of 20 V to unijunction transistor Ql, except at the end of each half-cycle of the input when the line voltage drops to zero. Initially, the voltage across capacitor Cl is zero and capacitor C2 cannot charge to trigger....
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The circuit has a frequency response ranging from 100Hz to 3 MHz; gain is about 30 dB. Field-effect transistor Q1 is configured in the common-source self-biased mode. Optional resistor R1 allows you to set the input impedance to any desired value; commonly,....
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A loop antenna is a radio antenna consisting of a loop (or loops) of wire, tubing, or other electrical conductor with its ends connected to a balanced transmission line. Within this physical description there are two very distinct antenna designs: the small....
Boosters are not buffers! While it is possible to make a booster that also provides a buffering action, the vast majority of the boosters commercially available ready-made or kits, do not have the proper design to be buffers. A buffer should have a high....
There are only 4 parts to the circuit, including the indicator LED. There is a hand-wound coil, a 1k resistor, a 2N4401 transistor and the LED. I quickly threw this together by just wiring the component leads together and it worked right away. The coil is....
The wah will work before the amplifier but sounds very low in volume and it sounds scratchy when the wah is rocked back and forth. The wah is fine without the buffer. In front of a fuzz face, with the fuzz face on, no sound passes Bizarre indeed. I`m going....
This is the complete schematic for the circuit that is contained on the AMZ Multi-Purpose PC Board. None of the example circuits will utilize every part that has been positioned on the board. Extra parts have been included to add flexibility and options to....
The classic Rangemaster is thought to have been the source of some of the best tones in rock guitar, from Clapton`s Beano sound to some of Brian May`s singing sustain tones. While the effect is a simple one-transistor booster, locating a good quality....
This project, based on an article published in the February 2008 edition of Radcom (the magazine of the Radio Society of Great Britain) is for a meter with a 50 ohm input impedance for measuring very small RF powers. Many RF power meters become inaccurate at....
Colpitts oscillators are somewhat similar to the shunt fed Hartley circuit except the Colpitts oscillator, instead of having a tapped inductor, utilises two series capacitors in its LC circuit. With the Colpitts oscillator the connection between these two....
Hartley oscillator are inductively coupled, variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor. This arrangement simplifies the....
An AM receiver relies upon the original carrier signal (station frequency) having been amplitude modulated. This means the original amplitude (strength) varies at an audio rate. Looking at figure 1 we can see an unmodulated carrier signal as it might be seen....
FM wireless Mike is a small electronic project based on a radio transmitter. It is a wonderful idea to make a wacky talky through which you can talk to your friend, next door. Just speak or play into the microphone and you ’ll broadcast to an FM receiver at....
This project is a wonderful idea of saving electric bill when you are using a heavy wattage bulbs. With miniature components and extreme care you can build a low power lamp dimmer right into the socket. Instead of a relativity expensive trigger diode, an....
At the point Vp the Emitter triggers and TURN the ujt ON, until this point ; the emitter is isolated(doesnt conduct) from the transistor so no Current Conduction occurs between Base1 and Base2...
The LDR is a variable resistor whose resistance decreases with increase in light intensity. When the light falling on an LDR has normal intensity, its Resistance is large enough and the voltage across R is insufficient to trigger the SCR. However, when light....
This circuit have an advantage over ordinary CONTINUITY testing Device, usually we are using multimeter to check the continuity of a circuit. It is not suitable to check the continuity of a circuit with high Impedence or resistance like Transformer,....
Here is the circuit diagram for simple door bell, you can assemble this circuit inside your room or home where as keep the switch outside your home or room that is easily noticable by the visitors. The working of this circuit is almost similar to my previous....
The timer IC(NE555) is wired as an ASTABLE MULTIVIBRATOR in this circuit. It will generate Alternating non sinusoidal output wave form at the instant we giving supply Voltage(12V). Thus primarily we generated Alternating Voltage from direct Current....
Assume initially, that there is a voltage Vc on capacitor C1 larger than Vbb-Vg. Where Vg is the cut in base to Emitter voltage and g represent Gamma. Hence the transistor is off and the capacitor C1 discharges exponentially towards ground with a time....
This circuit is also called as Free Running Oscillator. Because, it doesn`t requires any trigger pulse to get active. Consider the instant at which Vc=+Vsat. Now the capacitor charges exponentially towards +Vsat through R. Automatically, Vd increases and....
This circuit alarms whenever someone cross the Laser beam transmitted from a LASER. The output of IC TL071 goes high whenever their is no Light(Laser) Ray. This output voltage is further amplified by means of a NPN transistor Q2, which will drive the buzzer....
The circuit remains in stable state until a triggering signal is applied to its input. After getting the triggering signal the output transit from stable to Quasi-stable state and return back after a time period. So a Single Pulse isgenerated for single....
I am presenting you a 230V LED Driver circuit without transformer. Here i am using 5 led`s you can increase the count at your convineance. Due to the absence of Transformers we can reduce the cost and size of the circuit considerably. As we all know LED`s....
This circuit is composed of a temperature sensor, amplifier, V/F converter, three digit binary coded decimal (BCD) counter, time base and seven segment led displays. In addition to the 9400 V/F converter, other ICs need for this project include the LM334....
I am going to present you fabulous Electronic project, DEVICE CONTROL USING TIMER. By using this circuit you can turn ON an appliance at a desired time for a specific time interval. You can use this concept to control the operation of a furnace or central....
I am presenting you a simple smoke sensing alarm circuit using 555 timer. By using this circuit you can detect smoke and it alarms when the air is contaminated. Let me introduce you the components used in it. This smoke detecting alarm is based directly on....
The ultimate source of energy is Sun. it is possible to generate current from sunlight using solar panels. These panels convert light energy into electrical energy. A solar panel consisting of a number of solar cells, which will produce a small amount of....
An Operational amplifier based sine wave generator circuit, it is basically a wein bridge oscillator. Because of its simplicity and stability, one of the most commonly used audio frequency oscillator is wein-bridge. The wein bridge oscillator in which the....
A Simple Transistorized one Minute Delay Timer Circuit. It doesn`t include any complex or critical parts. You can use this circuit to generate a time delay of about one minute. That is, When you press the switch (Push button type is preferred) the LED turns....
A Tv remote jammer circuit, using NE555 timer IC. By using this you can watch your favorite TV channel without any interruptions. Ie; No one can be able to change the channel by means of remote, if the circuit remains ON. The circuit is simple to make at....
Ne555 is one of the most commonly used timer IC. It is a monolithic timing circuit that can produce accurate and highly stable time delays or oscillations. Like general purpose OP AMPs, it is very much reliable, easy to use and cheaper in cost. It has a....
Every innovations starts from a simple day to day life problem like you watching IPL in TV and suddenly the current shuts off, fortunately you will find another way to watch the match via mobile network. Similarly, I too had faced a problem of frequent....
This article helps you to make a Light Sensitive Morning Alarm circuit. The morning light is sensed by an LDR (Light Dependent Resistor) or Photoresistor and it triggers the alarming section. The circuit generates a melodious tone when light falls on it.....
Attached are 3 captures from my L297/L298 board using the same motor at 500, 750 and 900 steps/sec on a 36v supply, wired bipolar parallel (coil resistance = 3. 2ohm). This shows the A-enable signal (blue) and the sense voltage (red). The sense voltage is....
Tried to limit the number of wire jumpers in this board but things got a little tight since I was combining the microcontroller and motor driver in one board. It would have been a lot cleaner if I would have left the programming header off. The L298N is a....
This is another project which fullfills a need. I once built a frequency counter using plain TTL chips. That was long before the CMOS HC versions, even before LS was available. It uses only 4 chips - 3 HC TTL`s and an Atmel At90S2313 microcontroller. It has....
A simple function generator. Just to generate a certain frequency. While waiting for the AD9832 chip to arrive, I came up with a very simple version of the DDS synth, using just the 2313 and a resistor network. It`s controlled over RS232 from a small Windows....
Low-Pass and High-Pass audio output signal filters. Additional Sound Source Low Pass filter and experimental original design puls-gate signal filter ("processor"), both of which have independent or linked together Voltage Control input option. The....
The successive approximation Analog to Digital Converter(ADC) is probably the most common ADC. It requires few parts, and is simple to operate. Also, it always takes exactly the same amount of time to calculate the result. In a nutshell, it consists of a....
This is yet another variation on the "parallel resistor" dummy load. [Go -here- for a discussion on dummy load theory]. This is another one I built during my infatuation with copper pipe. It`s suitable for QRP HF operation of 5-watts or less average power,....
Simple modifications I`ve done on these rigs, to overcome some common shortcomings. Not all kits need these mods, but many do. Some overcomeminor inconveniences, and some potentially serious problems. If you have built one of these kits before, and....
The Coupe to USB adaptor - AKA `microwidget` is an inline adaptor to allow a laptop user running Windows 2k or Windows XP (it is as yet untested with Vista but should work) to interrogate the ECU on the Fiat Coupe. With suitable software, the ECU can be....
The clock is constructed on two boards; one carries the HT generator and the processor logic, the other the tubes. Thisallows a slightly more compact design that the previous effort, but didn`t save as much real estate as I`d hoped. The tubes are mounted on....
This web page describes the radio transmitter unit that flew aboard the Cirrus One rocket in April 2001. The intent of including the transmitter as payload was to: As the Cirrus One rocket was expected to achieve an altitude that would be well out of visual....
Before I began building amateur rockets, I built and flew model rockets, starting in the summer of 1971. Looking for a greater challenge, the following year I decided to begin building my own rockets, entirely from scratch. Although my first rocket was a....
This web page presents details regarding the design of a strain gage based load cell that can be used, in conjunction with an electronic data acquisition (DAQ) system, for static thrust measurement of a rocket motor. The load cell described here is meant to....
I have one Meanwell LED driver of 27V, 2300mA on hand and will be running 2 strings of 6 LEDs in parallel. Should I follow the same circuit with same component value or should I need to change the value of the resistors to my configuration "The addition of a....
I experienced faulty DS18B20 reads on my tank thermometers, probably due to my heatshrink/silicone waterproofing method. It gave me a chance to improve my code to make the controller more tolerant of bad reads, but my tank thermometers have now been replaced....
The memory part of my Mark 2 system is extremely simple. There are two 32K SRAM chips (actually FRAM because I had them lying around, but there isn`t any significant difference in this application). These are selected with the logical OR of the MREQ signal....
The basic requirement was for some sort of output display and some sort of alpha-numeric input. So the simplest solution I could think of was a UART, attached to something with a screen and keyboard running a serial terminal. I looked at using the PIC....
The H-bridge is a circuit used in electronic control of high current devices, particularly where the device polarity may be reversed, e. g. DC motors. The name comes from the fact that the circuit typically looks like a letter "H". The circuit shown has four....
The term amplifier as used in this article can mean either a circuit (or stage) using a single active device or a complete system such as a packaged audio hi-fi amplifier. An electronic amplifier is a device for increasing the power of a signal. It does this....
A hydraulic or hydrostatic drive system or hydraulic power transmission is a drive or transmission system that uses hydraulic fluid under pressureto drive machinery. The term hydrostatic refers to the transfer of energy from flow and pressure, not from the....
A multivibrator is an electronic circuit used to implement a variety of simple two-state systems such as oscillators, timers and flip-flops. The most common form is the astable or oscillating type, which generates a square wave - the high level of harmonics....
To generate and maintain the EP, perilymphatic K+ enters fibrocytes (F) via Na+/K+-ATPase and Na-K-Cl cotransporter. Gap junction networks connect fibrocytes to strial basal (SB) and intermediate (SI) cells, allowing ions to enter the intrastrial space via....
An illustration of the electronic impedances of a solid-state nanopore chip. (b) Simplified circuit schematic of the voltage-clamp current preamplifier. (c) Circuit design of the low-noise current source that substitutes for a feedback resistance (RF). (d)....
Circuit schematic of the UDC containing only dispersive components. The two low-frequency series LC resonators (with LA=LB and CA=CB) are fed by two input semi-infinite transmission lines, A and B, and parametrically coupled to a third high-frequency series....
This section contains details for providing a composite video output signal from the camera to drive an external monitor. The circuit described below, designed by Peter Smith, is a combined DC-restorer, switchable gamma corrector and video/sync mixer using a....
To get the best from an NBTV signal it is important to use the full dynamic range of the signal with no crushing at black level or peak white. To check the linearity of a video path it is usual to use either a staircase or sawtooth test signal. The circuit....
With the recent events at the Fukushima Dai-ichi nuclear power plant, I thought it would be pretty cool to build a Geiger Counter and hook it up to my NerdKit for interfacing with my computer. I`ve found this article which explains the building process....
Control a fan using an LM34 temp sensor and a computer fan with model number : ASB0912L. I used a 2N7000 mosfet transistor as a switch. I want my fan to run at 35% duty cyle when the temperature is above 77 fahrenheit and to run at 0% duty cycle when....
Read and write the raw data from an SD card using just a computer (no microprocessor) forgetting the FAT32. I would like to do this in basic C. I can look at the raw data with a program called winhex. Long run I want someone who is less computer savvy to run....
The point being if it connects it`s good if it don`t it don`t, there`s no inbetween. If you got a solder joint it`s going to connect or it`s not going to connect, that`s it. 0. 25 to 4ohms come on really. Do they even make resistors that small to set it with....
There are two major types of backlights for LCDs: LEDs, which stands for light emitting diode, or EL, which stands for electroluminescent. EL backlights tend to be more efficient and have more uniform lighting than LED ones, but they require some tricky....
This project uses a magnetic reed switch, a NerdKit, and set of computer speakers to frighten unsuspecting visitors at the door. In covering constructing this project, we get a chance to go over some pretty neat engineering concepts: digital audio, data....
Using the OBD-II (On Board Diagnostics) protocol, we can read live information from a car`s computer with our NerdKits microcontroller kit, as explained by our guest star, Elena T. , MIT class of 2011. This uses the port under your steering wheel to receive....
We always like to use Halloween as a chance to show off neat homemade electronics to the general public. In this special Halloween video tutorial, we have recreated the idea behind a musical instrument called the theremin, and built one into a Halloween....
Marx Generators are often used in pulsed power and high voltage applications to generate a high peak voltage pulse. The simplified theory behind them is that a number of capacitors are charged in parallel and then switches are closed to connect them in....
build an interface board to connect some scientific equipment (for me, a pair of photovoltaic tubes) to a personal computer to acquire measurements results. Signal properties were following: two channels with a common ground, 1 second of acquisition time,....
The circuit of the unit is fairly simple, but is a bit irksome to set up. The reason is that obtaining matched FETs is not easy, so I had to make sure that the circuit would work with off-the-shelf FETs. The phase shifter is a standard opamp circuit, and has....
Each CdS cell acts as a variable resistor in a single variable phase-shift circuit and there are six such individual phase shifters arranged in series, each increasing the overall shift. The LED`s brightness is modulated by an oscillator (bottom section of....
This simple circuit generates both white and pin noise. Transistor Q1 is used as a zener diode. The normal base-emitter junction is reverse-biased and goes into zener breakdown at about 7 to 8 volts. The zener noise current from Q G flows into the base of Q2....
The heart of the circuit is IC2, a 50240 top-octave generator. That device uses a single input-frequency to generate all twelve notes of the musical scale. The input signal is provided by IC1, a 4001 quad 2-input NOR gate. Two sections of that IC are used to....
The circuit consists of a white noise generator which only switches on with the high part of the square wave output from the clock circuit. The frequency of the clock is adjusted with the 10 pot and the output voltage of the clock is adjusted by the 100 k....
I have made a major correction to the schematic as a result of getting a second board going. The manual sweep circuit should return to ground not vref. I also increased the feedback limiting resistor from 100K to 270K. This area of the circuit might bear....
Unfortunatately this only provides 1. 8v signals and still needs a converter to interface to the 3. 3v signals most raw LCD use. The main components is the TFP101A. I got mine as a free sample from TI. Also visible in this picture is the fact that only the....
This circuit, which was developed to monitor the traffic of bumblebees in and out of the hive, differentiates a-to-b motion from b-to-b motion. When used with an optical decoder, the circuit distinguishes clockwise from counterclockwise rotation and provides....
This circuit consists of an amplifier and video detector with a second subcarrier detector for synch recovery purposes. A pulse-former circuit modulates the gain of the main channel increasing it during synch intervals...
The zener provides a constant voltage of 20 V to unijunction transistor Ql, except at the end of each half-cycle of the input when the line voltage drops to zero. Initially, the voltage across capacitor Cl is zero and capacitor C2 cannot charge to trigger....
The circuit has a frequency response ranging from 100Hz to 3 MHz; gain is about 30 dB. Field-effect transistor Q1 is configured in the common-source self-biased mode. Optional resistor R1 allows you to set the input impedance to any desired value; commonly,....
A loop antenna is a radio antenna consisting of a loop (or loops) of wire, tubing, or other electrical conductor with its ends connected to a balanced transmission line. Within this physical description there are two very distinct antenna designs: the small....
