Top Circuits Page 219
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Designed the same thing but for the reason of having a higher output voltage swing for the mono part of the signal. I personally don`t believe/understand Meier`s idea as voltages are just relative anyway aren`t they I haven`t read this entire thread but from....
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It can be simplified and you can leave out short-circuit protection if you wish. This circuit is a Mosfet-based linear voltage regulator with a voltage drop of as low as 60mV at 1A. The circuit uses a 15V-0-15V transformer and employs an IRF540 N-channel....
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The size of the tread was 5cm by 3cm. My design, at the moment is 5cm by 3. 3cm. The basis of the regulator is taken from Walt Jung`s 1997 article Regulator Excels In Noise and Line Rejection. With a few changes based upon other Walt Jung articles on....
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Tested all the resistors and noted 2 resistors` readings were out compared to the other channel (i. e.1. 2Kohm vs 2. 2 kohm). Based on the color codes, should be 2. 2kohm. THought I spotted the problem, repl the "1. 2kohms" with new 2. 2 kohms but the....
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This project allows one to build a very high quality version of the Stax SRD-7MkII headphone adapter to allow one to use an existing favorite amplifier to power your stax headphones. (Let Birgir know what amplifier you have to find out if the adapter is....
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Two KOSS A-1220 headphone amps. Each share the same model number, yet have completely different internals: One uses just a single 12AU7, while the other has a 12AT7 and a pair of 6AQ5A`s. I have searched the forums and found one or two threads about this....
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It`s just a AN2131 chip with the required support circuitry - crystal oscillator, power regulators etc. First I took the inputs and outputs of the key matrix and wired them to the GPIO ports of the AN2131. This was just a matter of plugging the whole lot....
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It requires no doctors, drugs, or medical bills. The procedure involves sterilizing the blood of viruses, bacteria, parasites, fungus, microbes, pathogens, mycotoxins and coexisting foreign life forms and alien invaders and their byproducts by passing a....
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This board does NOT use the CTS256AL2 text-to-speech chip. [It would seem that both SpeechChips.com and JDR still have some of these chips, though, if you're looking for some.] However, you could easily use this board to hold the SPO chip and amplifier and....
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However since the ROM is mapped in at &F000, this in binary is %1111 0000 0000 0000; or in other words when accessing the ROM, A12, A13, A14, and A15 will always be high. Thus, the I/O device selections will always be active at the same time as the ROM....
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The most simply way to collect all this free available energy is to use solar cells. One good solar cell in combination with one well configured hho generator can produce a lot of gas that can be used for all kind of applications. And the best, never pay one....
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This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching....
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This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of....
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This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
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Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring....
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an efficient flyback driver for modern cylindrical rectified television flybacks. Many sites doesn`t provide circuits driving these transformers, they simply say that they are bad. I don`t agree. In fact I built this circuit. I spent a lot of time for....
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The 60 Watt linear amplifier is simple all solid state circuit using power mosfet IRF840. The IRF series of power transistors are available in various voltage and power ratings. A single IRF840 can handle maximum power output of 125 watts. Since these....
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This circuit controls a load (in this case a dc brushless fan) based on a temperature compared with a setpoint. THe transduced is a diode in the forward polarization regime. In fact when forward biased, the forward voltage drop accross a diode has a....
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This simple circuit drives 6 LEDs in `Knightrider scanner mode`. Power consumption depends mainly on the type of LEDs used if you use a 7555 (555 CMOS version). We are not responsible for any injuries or damage caused by information from this website!....
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The power line fluctuations and cut-offs cause damages to electrical appliances connected to the line. It is more serious in the case of domestic appliances like fridge and air conditioners. If a fridge is operated on low voltage, excessive current flows....
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We will describe the function of a digital stopwatch, 0 G 99 sec. The function of the stopwatch, relies in the use of 4 integrated circuits, which in this case belong to National Semiconductor ( It is obvious that other integrated circuits can be used to....
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This circuit uses the versatile MAX038 function generator. Although in this circuit some of the advanced characteristics of this IC are disabled, you can generate Sine, Triangle, Square waves (adjusting A0 and A1 pins see datasheet on if you want other....
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can be arranged in a circle to represent the 12 hours of a clock face and an additional 12 LEDs can be arranged in an outer circle to indicate 5 minute intervals within the hour. 4 additional LEDs are used to indicate 1 to 4 minutes of time..
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A low noise circuit equipped with a variable voltage-gain (10 - 100) pre-set, primarily intended as high quality microphone input, also suitable for low-level line input. Tone Control Module: a three-band (Bass, Middle, Treble) tone control circuit providing....
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This circuit is a Digital Radar Speedometer. It allows us to evaluate the speed of any object moving, especially cars and other vehicles. The speed is calculated in kilometers per hour (KPH). Its display has three digits. This radar works with the laser....
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This design is based on the 18 Watt Audio Amplifier, and was developed mainly to satisfy the requests of correspondents unable to locate the TLE2141C chip. It uses the widespread NE5532 Dual IC but, obviously, its power output will be comprised in the 9. 5 -....
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This is a fun and non-dangeros project for those people who like to throw projectiles magnetically. It simply works by placing a ferromagnetic projectile at one end of a coil and pulsing some power in it. The trick is to switch off power when the projectile....
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U1a operates as a low-noise microphone preamp. Its gain is only about 3. 9 because the high output impedance of the drain of the FET inside the electret microphone causes U1aG ™s effective input resistor to be about 12. 2K. C2 has a fairly high value in....
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The thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees celsius. A suitable bead type thermistor is found in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of temperatures. A slight amount of....
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This is a very interesting project with many practical applications in security and alarm systems for homes, shops and cars. It consists of a set of ultrasonic receiver and transmitter which operate at the same frequency. When something moves in the area....
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This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor`s output voltage proportional to the measured temperature. The output frequency bursts are conveyed into the mains supply....
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This circuit is an Electronic Locker. It is controlled by a switches combination (by a code). There is a switch matrix on the door of the locker. This one is a unit of switches connected into 4 arranged of 4 columns for a total of eight terminals. When we....
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This is a new design of a tutorial board based on the popular PIC16F84A microcontroller. It features eight single leds, a 7-segment display, an LCD display and five push buttons. It is an ideal solution for the beginner to take his/her first programming....
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Diode D1 and resistor R1 provide the VDD isolation when programming the 24 pin devices. The jumper J3 must be shorted for 24 pin devices, and open circuit for 28 pin device programming. Following EEPROMs are pin compatible with their EPROMs version, We are....
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The sound produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors is discharged and both transistors are off. When the push button switch is pressed to 10u capacitor will charge via the 22k resistor. This....
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This tester is designed to locate stray electromagnetic (EM) fields. It will easily detect both audio and RF signals up to frequencies of around 100kHz. Note, however that this circuit is NOT a metal detector, but will detect metal wiring if it conducting ac....
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This simple circuit mixes two or more channels into one channel (eg. stereo into mono). The circuit can mix as many or as few channels as you like and consumes very little power. The mixer is shown with two inputs, but you can add as many as you want by just....
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The circuit is simple, yet is capable of excellent performance. I designed it specifically for use as an amplifier for the digital sound card in my computer. Audio input can be from any two-channel line level device such as a television, CD player, or VCR.....
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The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of....
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This is a very simple, low cost, Hi-Fi quality power amplifier. You can build it 5 ways, like its shown in the table (from 20 W to 80 W RMS)....
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Small and interesting circuit that flashes your head lights. Automotive, head lights, circuit diagram. Built around famous NE555 timer circuit....
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This simple circuit can be wired into your headlight switch to provide automatic switching between high and low beam headlights when there is oncoming traffic. Simple electronics project with circuit diagram....
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This charger will quickly and easily charge most any lead acid battery. Electronics project, easy to build, with circuit diagram included....
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Interesting light for your bicycle. Made of LEDs. Very nice! Low power consumption, circuit diagram, electronics project, 9V, NE555....
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This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source. Electronics project....
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This circuit above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0. 7 Volts are dropped across the transistors b-e junction, leaving a higher current 12. 3 Volt output supply. This circuit can supply loads of up to 500....
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This dual polarity power supply is easy to build, requires few parts, and is adjustable from 0-15 volts. It is great for powering op amp circuits, as well as other circuits that require a dual supply voltage. 4. U1 and U2 can only go down to a minimum of....
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This is a fun and useful circuit for demonstrating high frequency high voltge. It can produce up to about 30KV, depending on the transformer used. It is cheap and easy to make, thanks to the standard TV flyback transformer used. It can power LASERS (although....
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This version of the Link is for those who really need a good cheap intercom that will work reliably, but without access to an outside Telco line. This could be in a pre school, a hobby farm or a small workshop or factory, where external phone traffic needs....
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A circuit and arduino code to approximately emulate a ScratchBoard ; there is sound, light, a button and four sliders but it isn`t a drop-in replacement. remember to change the COM ports in the Arduino IDE and in Scratch so that they are not competing (if....
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Voltage Controlled Shape on each Oscillator, Calibrated 1V/Octave Keyboard Input, External Gate Input socket, Portamento/Glide, Patchable Voltage Inverter, Extra Input Channels, Better Panel Components, Power Supply Replacement, Mains Connectors....
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An advantage that a photogate has over a sound trigger is that the former triggers on the precise location of the object that breaks the beam. For example, the shape of a snapped elastic cord can be photographed as it passes through the beam. While a....
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Wireless power transfer is nothing new; it has been discussed since Tesla`s patent in 1900 entitled "Apparatus for Transmission of Electrical Energy" (USPTO #649, 621). However, as the technology matures, it will be interesting to see what myriad....
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With the equipment ready for operation, the main line switch (S-831), the EMERGENCY SWITCH (S-12) and the main line contactor contacts K-831B all are closed. (1) The keying relay main contacts (K-1C) ground the center tap of the MO filament secondary of T-1....
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The tuned circuits of capacity and inductance used in vacuum tube transmitter circuits are frequently called "tank" circuits, because from one viewpoint they act as tanks or reservoirs of RF energy. Blocking Capacitors. -Blocking capacitors are used to....
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The receiving systems used with the scanning type of echo-ranging equipments are of the dual-channel type, which is required in present methods of video portrayal. Deviation indicators, which are cathode-ray tubes or galvanometers, use either a....
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A prescaler attached to a PIC to get a simple frequency counter. I would suspect that it would just become a "module" that I include in some other design projects later. Initially I need to get a working sample. Target range would be 1mhz through 400mhz...
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This two-zone alarm has automatic exit, entry and siren cut-off timers. It was developed for the Beginner`s Guide To Cmos Timers. So it has a particularly detailed circuit description. There`s an optional One-Time-Only module. It will force the siren to....
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This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. It has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. By using the Expansion Modules, you can add as many zones as you....
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This transistor based alarm features automatic Exit and Entry delays - together with a timed Bell Cut-off and system Reset. Along with the Exit/Entry zone - the basic alarm board has one Instant Zone. This will be adequate in many situations. However - the....
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The circuit features automatic Exit and Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open and normally-closed switches and will suit the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape, PIRs and....
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This circuit features automatic Exit and Entry delays - timed bell cut-off - and system reset. It has provision for normally-open and normally-closed switches - and will suit all of the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape,....
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This is a simple single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays and a timed Bell/Siren Cut-Off. It`s designed to be used with the usual types of normally-closed input devices such as - magnetic reed contacts - micro....
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This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of normally-closed input devices - such as magnetic reed contacts, foil tape, PIRs etc. But it`s easy to add a normally-open trigger.....
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This is a selection of small self-contained alarm circuits. They have a very low standby current; and are suitable for battery operation. Some are triggered by normally-open and normally-closed switches. Some react to changes in light or temperature. The....
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This circuit will let you know when something that should be kept closed - has in fact been left open. Attach it to a Fire-Door. It will allow you to pass through the door as usual. However, if it`s left open for more than 30-seconds or so - the buzzer will....
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This is an enhanced version of the simple Garage/Shed Alarm. The Entry and Exit delays have been increased to about 30-seconds - and I`ve added a timed Siren cut-off and automatic Reset. I`ve also replaced the LED with an entry Buzzer. These enhancements....
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This alarm circuit was designed to monitor a mains-powered smoke detector located in a shed (which is used to house dog kennels). It provides complete isolation from the mains so that low-voltage (12V) cabling could be run to the alarm circuit which is....
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This car alarm circuit features Exit and Entry delays, an instant alarm zone, an intermittent siren output and automatic Reset. By adding external relays you can immobilize the vehicle and flash the lights....
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Like the first two Hijack Alarms - if a door is opened while the ignition is switched on - the circuit will trip. And after a few minutes delay - when the thief is at a safe distance - the Siren will sound. But this time the engine does not go on to fail....
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This is a Universal version of the Four-Digit Alarm Control Keypad. I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. I`ve used a SPCO/SPDT relay - but you can use a multi-pole relay if....