Top Circuits Page 218
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The Glolab ED4GP microprocessor based Encoder / Decoder is designed for use with wireless modules, infrared remote controls and other devices that operate with serial input and output data. It can be used as either an encoder or a decoder by simply....
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The GLMDPCB motion detector board is a double sided etched, screened and drilled printed circuit board designed for the GLMDA motion detector circuit shown in the schematic below. All or part of the circuit can be built. For some robotic and other special....
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It is easy to install 6E5 on the place of oscillator tube because socket`s pinout of this amazing valve is nearly the same to pinout of common 6J5 and 6C5 triodes. So, you can replace these tubes with The Magic Eye without any soldering. But if you want to....
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A Super-Duper Powerful Vacuum Tube QRP amplifier for my 800mW QRPP homebrew telegraph vacuum tube transceiver "3T" (I promise to write a separate article or two about this three tube transceiver project later). It was not an easy decision to me because for....
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TPTG transmitter was transformed into a trendy TNT. You can use your present K-111 power pack for this transmitter as well as for the receiver, and thus save the expense of a separate power supply unit. Build this little transmitter and go "on the air. " The....
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A wireless interface for your next project Got some wire With a coil, a cap and a transistor, you can make your next project emulate a Radio Frequency Identification Device (RFID), commonly called a "tag" or an "RFID tag. " Here`s how. A device usually....
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By selecting "ON" mode the the SilverPro© start the process of generating the colloidal using the your presetSetup parameters. The unit allways recall the last used presets. During it`s operation the display scrolls between the total minutes elapsed, the....
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You wire in some relays and run it in parallel with your key ignition. The wiring schematic is as follows: So do I connect one wire from the 87 terminal (orange) to the red wire, then the blue wire from the next relay to the black wire and so forth I....
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A power filter is a device you put ahead of something like a GPS and MP3 player and or radar detector that you have run into the Aux Circuit. But these things used properly and properly installed will take the modulator noise out of any system. If you were....
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Two-phase hybrid stepping motor dynamic voltage 12 to 48V, the current is less than 5A outer diameter of 35 to 86 mm. This drive using the drive`s current loop subdivision control, the motor torque ripple is very small, low-speed running is very smooth,....
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How to design an antenna for the MICORE contactless reader IC family. (The MIFORE reader IC family includes the MF RC500, MF RC530, MF RC531, SL RC 400 and the CL RC 632. The antenna design and matching is the same for all of these ICs. ) For a good overview....
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The Motor30 board is an H-bridge for delivering up 30 Amperes of current to a motor. In addition, it has an on-board hall-effect shaft angle sensor. The module is fully opto-isolated to keep motor noise from leaking across to the logic power supply...
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While the Jacob`s Ladder is simple to construct, the operation is quite interesting. The spark starts at the bottom where the gap between the wires is close and then heat makes the plasma rise and stretch between the electrodes until there is no longer....
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One 1381 part (CMOS voltage-controlled trigger available at different limits) Get one that matches the voltage across your motor (2V in this case) 8. The other terminal of the motor is connected to the 3300uf capacitor which is in turn connected to the other....
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Above is a schematic diagram of a type of audio oscillator known as a twin "T" phase shift oscillator. It gets its name from the phase shift network made up of R3, R4 and C3 plus C1, C2 and R2 which shifts the phase of the signal fed back from the collector....
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AM radio receivers receive or demodulate amplitude modulated (AM) signals. The most common source of these signals is of course todays Standard AM Radio Broadcast Band but shortwave stations use AM modulation as well. Amplitude modulation was really....
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The Amstrad CPC 464 was released in 1984 and discontinued in 1990. It was possible to purchase a CPC 464 with a green screen (GT64) as well as with the standard colour screen (CTM640). Like most 8bits computers, the CPC has it`s OS (aka Firmware ) and a....
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GVI Digital Remote Control for DSLR camera is a step forward from my previous remote control for Canon EOS 450D. This remote is based on AVR Microcontroller ATmega328 and is programmed using Arduino IDE GVI Digital Remote Control is a tool for photographers....
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To demonstrate Rincon`s capability to simulate autonomous circuits, let us consider one-transistor oscillator, which uses phase-inverting resonance T-shape LC circuit. Schematic of this simulator is shown at fig. 1. Design of simulator is described in....
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Graphic equalisers are made of 15 or 30 band-pass filters, one for each 1/3 octave frequency. Conventional equaliser designs use standard discrete components to realise these band-pass filters. Apex GX- and PE- series achieved far better results by using....
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This circuit provides either latched switching or timed switching. U1A and U1B provide audio ampliftcation from the microphone, U2 is a retriggerable monostable multivibrator. S1A and S1B select either U3, a flip flop, or U2. R13 and R14 allow a 6 to....
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This project is almost useless, I want just to realize a pendulum that swings endless. Nothing more. No use at all. This is not an original project but my version of a project of the past century, already seen in many different ways on the Net. This is my....
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As described in the block diagram page, this is the system that provides power supply for all the circuitry of the whole robot. In the aluminum box there are the NiMH cells and all the circuits already described. There are two lines of preregulators to....
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A module of modules: 3 dome filters, 4 ring modulators and some summing/differencing amps (mixers). Each additional slave requires an additional dome filter, pair of modulators, and mixers. I built my prototype as one "master" and one "slave". I used more....
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This is a really good project for anyone wanting a good old fashioned tremelo pedal using the original optical coupling technology employed in such things as the Reslytone RT-18. I reckon it`s pretty unique with what`s around. There are any number of tremelo....
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The Sennheiser Dummy Head Stereo recording was a huge breakthrough in the concept of recording at the time. It enabled the reproduction of 3D information as our ears perceive it. The other day I received an email from someone who happened upon this page. He....
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The meter came from eBay, and has a 1 mA full scale movement. It was already marked 0 to 100. I simply removed the original scale, scanned it, and added the "% NETWORK" markings over some of the original ones with an image editor. I then printed the new....
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The output assign modules uses a 16V8 GAL for address decoding and enable signal generation. Figure 44 shows the pin assignments for the GAL used in the output assign module. The VHDL code used to generate the GALs is included in the appendices, on page The....
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The Practical Shop Work Mark is based on productivity, work habits, safety and cleanup while working on assigned projects, or assigned labs. The student will fill out a Technical Activity Report of work completed at the end of each period which will be....
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This pages contain information about building your own version of the Calrec PQ1549 Equalizer, the one found in the Calrec "Polar" desk. This EQ is one of my absolute favorites when it comes to standard IC-based types, so I made this project to make it....
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My design is somewhat like a combination of the circuits in M49 and U47, but mounted with the tube used in U67. There`s really not a lot of complicated electronics here. This is a true variable-pattern microphone, capable of doing omni, cardiod and....
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The G9 project is an adaptation of the Gyratec IX dual microphone/line/DI preamplifier to suit the DIY`ers demands. Searching the net, I`ve never come across a complete tube microphone preamp design, so I decided to share this version of our very popular....
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Here`s some schematics and information that can be hard to find elsewhere. If you have some schematics that you think belongs among these, please do not hesitate to contact me. I hope to be able to extend this little collection with time, so check back for....
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A 3-dimensional LED cube, which I can program, to create Art. No more "Doug Stick Figures", but something really cool. Follow along as I create Art. I looked through my parts bins to see if I had any microcontrollers left over as I was planning on doing the....
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This interface became a standard to almost all operating systems we know today. IDEfile is a ProFile compatible hard drive for Apple /// and Lisa systems. Emulation of the classic 5MB ProFile and the rare ProFile 10M is provided. I intend to support....
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The Clarinet preamplifier is agile, detailed, and warm without being euphonic. It has excellent soundstaging, tonal balance, presence, and palpability. It is far better than any of the other kit preamplifiers I have heard to date, and is worth your serious....
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This little phono stage completely trounced my sub-mini phono preamp. The phono preamp was extremely quiet with my vintage Grado 8MR cartridge (not MC). This is not a vintage-sounding phono preamp. While it sounds pleasant and definately tube-based, it has....
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The Cymbal monoblock power amplifier is a unique and modern push-pull design using ultra-linear 6H30 triodes in a zero-feedback circuit. The uncommon circuit is optimized for sonics rather than raw power. Perfect for efficient drivers and horns, its eight....
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The Hakkit robotics shield is a breakout kit for the Arduino Uno R3. When assembled the shield gives five standard servo headers taking advantage of the PWM pins on the Arduino and breaks out the analog pins to give six inputs for sensors. This shield is the....
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This page identifies all the hardware modifications necessary to adapt a Kenwood TK-931 transceiver for operation as a 2 watt exciter for 927 MHz repeater service. Not shown here is the effort required to program the radio for the desired operating....
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This page identifies all the hardware modifications necessary to adapt a Kenwood TK-931 transceiver for 902 MHz repeater receive operation. Not shown here is the effort required to program the radio for the desired operating frequency. This is accomplished....
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The 751 required turning the volume control almost to 12 o`clock before getting any hearable volume so I thought maybe something was wrong here. I replaced all the electrolytics associated with the audio path, i. e. after the detector stage and the audo amp.....
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I have been getting a lot of emails about this project. Most of them are because of the bad source code listing at the end of the author`s notes. I have seen this problem all over the web and I too have ran into the same problem when compiling the code. I am....
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Anyone who wants to understand IR remote controls and how they function, this project will be great for you. This circuit I found online seems so simple and uses my favorite programmable chip company (Microchip). There really isn`t a FULL tutorial from start....
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The beacon controller is intended to be operated for telemetering data available on board of the VUSAT in Morse code so that the ham radio operator can decode the info without any costly and complex equipment. The design strictly follows the KISS concept. It....
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TNC and Modems ruled the world of digital communications until recently. With the advent of high speed computing and digital signal processing (DSP) all this has changed. If you own a home computer (PC) with a sound card, all you need to do is download....
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The frequency counter has to count the number of cycles per second of an incoming signal. Hence we need a device to count. In electronics circuits, counter ICs are available for counting. These IC`s can count the input pulses. The count is given as coded....
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This is a new gear for Radio Direction Finding (RDF) known as FOX HUNT or called Transmitter Hunting (T-Hunting) or Treassure Hunting. HAM clubs, all over the world, are conducting this SCIENTIFIC GAME occasionally, being which is the only one interesting....
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To make a battery operated LED lamp, it may better to use a cluster of low power discrete LED array rather than a single high power LED. The light produced will be scattered and It considerably reduces irritation or damages to a naked eye, if accidentally....
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A well tuned antenna system works like a dummy load, i. e. the SWR is 1. 2:1 or below but the hunting range is low. What`s wrong Insufficient radiation How to know that Yes, this is what the article about. You can measure the effective radiation using a....
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This is a simple frequency counter based on a micro-controller PIC16F84. Its maximum working frequency is around 30MHz, and have a 10Hz resolution, and having low current consumption (15mA), and very simple assembly. This uses 7 numbers seven segment LED....
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The Frequency instability in VFO stage is a common problem. This is usually occurred in VFO`s due to low Q of the tank circuit, capacitors real value, power supply regulation, stray capacitance, lead inductances and over feed back levels etc. Few months....
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A model RTX-70 exciter that was originally used in the Brookdale ATV Repeater System. This page describes some the design considerations and new features possible with this new exciter, and includes schematics of the circuits designed during the exciter`s....
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The HANDI-Finder ® is a HANdheld DIrection Finder which can be used to localize both AM and FM carrier-based sources using a single connection to the antenna input of an FM receiver tuned to the frequency of interest in the range of 45 to 450 MHz. It has....
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The A4988 driver IC has a maximum current rating of 2A per coil, but the actual current you can deliver depends on how well you can keep the IC cool. The carrier’s printed circuit board is designed to draw heat out of the IC, but to supply more than....
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I`ve now come to see cosmic ray detection as the poor man`s version of particle physics experiments. As the journey of construction, experimentation and interpretation of results, has meant learning a little bit more about the fascinating particles and....
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This hack replaces the thermistor (temperature sensor) of a hot tub with an adjustable value that will fool the hot tub controller into thinking that the water is a certain temperature. In addition, this circuit is turned on and off by a 24VAC line....
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Inexpensive buffer circuit suitable for using to mix passive pickups with EMG active pickups, or buffering piezo pickups to mix with magnetics. Frequency response is pretty much flat, and noise is fairly comparable to passive pickups if built correctly. The....
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The first schematic is for those who never buy parts anywhere but Radio Shack. You can walk in the store and walk out with all the electronics that you need. For the heat sink, sorry to say, you`re on your own. Find a hardware store and buy a big chunk of....
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Above, the saturation region starts at the knees on the left. We`re interested in curves for negative gate voltages (depletion mode). Note that this device also operates in enhancement mode (with positive bias)! Flexibility. The construction method for this....
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J201 JFET works best at 10 volts. The minimum current is 0. 5 mA. These are all ideal specifications. The specification spread of FETs is normally three to five times. I`ve personally seen a five-X variation in brand-name devices. The devices that I`ve....
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The circuit that I`ve described is a one-JFET design without much gain. You can significantly boost the gain by adding a source resistor bypass capacitor. The result would be something like one stage of the original tube preamp in a guitar amplifier. Next,....
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A Darlington would perform even better, but the circuit would be slightly more complicated. (See the schematic at bottom-right. ) Fortunately, the added complexity is inside the part! The reason for the Darlington`s superiority is that it can provide the....
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With an an input sinewave on the left amplifier base, here`s what happens: The collector output rises above or falls below 6. 6 volts. Of course, the amplifier increases signal level and inverts the signal. Because the output is roughly centered, the chances....
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JFET input. PN photodiodes such as the popular "bullet cell" put out an extremely low-level signal. Yet photodiodes offer advantages over phototransistors. For example, more rapid response to motion. Also, some photodiodes have a peak response in the range....
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The color wheel and motor control are up to you. Yes, this is field-sequential color, not the "compatible color" that came along a few years later. After we detail the wiring changes, we`ll tell you more about the wheel. Anyway, even without the wheel,....
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d 101-2 depend on the TV to supply a wide bandwidth video signal. Most black-and-white TVs from 1954 on contain narrowband IF strips or low-pass filters. A wide passband is a disadvantage, because it picks up the chroma signal. In a black-and-white TV, the....
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Build a two-color camera and a three-color monitor. You can build your camera to pick up any two of the additive primary colors. Just install the proper color filters over the phototransistors or photodiodes. With a matrix circuit and an inverter, you will....
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amplifier, with bias at cutoff. Q5 acts much like a grid-leak detector. Without the subcarrier input, the demodulator cuts off and prevents signals from passing. Of course, the chroma signal must be at a low level. Otherwise, chroma might gate the....
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Despite the high impedance of its inputs, Darlington Q10 develops enough current to drive an LED. The inverted output of Q10 drives opto U5`s internal LED. Opto U5 couples to motor-control triac CR1. Motor Voltage Control Triac CR1. Triac CR1 is a....
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Calibrating the Smiths electronic tachometer some time ago when I realized that my tach was completely out of calibration. I used a technique similar to the one described in Tom Ballous 1975 Tech Tip to calibrate my tach at about 1200RPM using my dwell/tach....
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A simple lab-psu using the lm317, based on the first schematic. to prevent damages to my dmm when measuring mA, i`d like to include a switchable current limiter. but i`m not sure if i understand those schematics and how i could integrate it. so here are my....
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A low pass filter is merely a stable state-space system that has an input and spits out an output. If the input is a quasi-periodic signal, then the output would simply be the same quasi-periodic signal with a phase shift. Only difference would be that this....
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Schematic shows R4 at the emmiter of the transistor, as amb and majkel have suggested it should be between the opamp and transistor, this is also the correct configuration in the canamp. The amp i managed to get a look at has been modified and has had the....
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Many audiophiles reject equalizers for various reasons, some of which relate not to the EQ circuit itself (or algorithm) but to the surrounding "glue" of op-amps, transistors, A/D and D/A converters etc. The only "passive" EQ I`m aware of is horribly....
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This is where the fun begin - the sound is hmm. "organic". Everything seems to smooth a bit compare to LME49720, a very subjective word. "musical" Also I hear more dynamics. Listening is best at extra high gain. Upon switching from LME49720, I actually hear....
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This is the version with 3 6N11 tubes. And as far as I can see identical to the Phenix. It looks and feels very well made. The separate power supply is a bit bulky but works well and keeps the size of the main box small and cute. The on/off switch is....
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I need one to put in between my headphones and my metal detector. I don`t need anything fancy, but would like to be able to use a pot and make it variable. I`m sure this can be done, I have looked and either don`t understand it, or it`s just not what I`m....
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The circuit is designed to run off a 100k volume pot, and be either a line stage or a headphone amplifier. It is a standard non-inverting gain stage (A=15dB) followed by discrete copy of the old LH0002 buffer IC. The basic idea is that the four transistors....
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Seems to me it uses at least as much power and at least as many components as a 4 channel balanced amp. it may well sound realy good and its quite clever, but does seem like a lot of trouble to go to `to travel the path less travelled` all the sameit really....