Popular Circuits Page 30
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How to use your existing infrared transmitter from any room in the house. The principal is really pretty simple, and it works better than you would think. This is a "very handy" little project. With this gadget you can control anything from pretty much....
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This simple PC parallel port ADC has 12 b resolution, four differential input channels and is it`s quite fast; the chip itself ( MAX186 ) is able to go up to 133 ksamples/s, but the actual speed will be determined by the software used. I wrote a simple C....
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The RF modulator is the very important component in TV, VCR, satellite receiver, format converter, home computer and game machine. This circuit is simple, stable and easy to make, it can be easily connected with a lot kinds of circuit boards. The figure is....
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1. Pressing `Roll` switch. When the switch is turned on T1
is turned off (its base is pulled high by the 3M3) and the
555 oscillator is not oscillating. Pressing the ROLL
switch immediately charges the 470nF capacitor, T1 is
turned ON and the 555 starts....
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I thought I would try to use a standard telephone earpiece`s inductance as the L of a Colpitts oscillator, and in so doing eliminate the need for a separate amplifer/buffer. ..
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This application note covers the design of a UHF ingress filter for a Satellite DBS tuner. The filter provides 20dB of stopband attenuation from 54-650MHz with 0.7dB in-band insertion loss....
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A power inverter converts DC power or direct current to standard AC power or alternating current. The following schematic shows a 12V power inverter Circuit Diagram...
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A little lightweight MFJ-4225MV power supply. It puts out about 25 A, maybe 20 continuous, which is enough for my IC-706GII or my new K3. I also liked the fact that the fan was fairly quiet. But that was in comparison with myFT-1000 with its fairly noisy fan....
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the circuit diagram of an AM transmitter circuit based on three transistors. With correct tuning and a matching antenna, the transmitter can ....
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Using the TDA7275A linear integrated circuit manufactured in a minidip plastic package can be designed a very simple speed regulator electronic project that can be used for speed regulation of small DC motors . TDA7275A DC speed controller project is....
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This is Single Cell LED Flashlight circuit. This circuit uses white LED that has best power-efficiency combination at about 20mA and requires abut 3.3V. Each....
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This circuit detects frequency variation above or below preset limits. IC1 is a binary counter docked at FcLK· The outputs are comparea with switch preset values by IC2 and IC3. The input signal, which must be a positive-going pulse, is used to reset IC1.....
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I originally wanted to call it Chimera , but then I remembered there`s already a synth company using that name, so I went with Cerberus to avoid confusion, and because Tricephalic Filter just doesn`t have the same ring to it. I didn`t bother renaming the....
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The basis of the electronic tachometer frequency converter circuit-current, which converts the input signal into a proportional current measured pointer device..
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High-precision voltage regulator, isolation transformer with the correct wiring and low-pass filter, to further improve the electrical noise immunity source portion. The wiring in Figure 20-48 and 20-49 as shown in FIG. Figure, chokes (Li, Lz) choose an inner..
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R2 sets the circuit"s threshold. When the light intensity at PCI"s surface is decreased, the resistance of PCI a cadmium-sulfide photo-resistor is increased. This decreases the voltage at the inverting input of the 741. When the reference voltage at the....
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Activities Modern exhibition, advertising, promotion and propaganda extensive use of sound, light, electricity technology, a number of electrical diagrams, control model, commo..
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By the CW4962, CW4960 constituted + 5V/1.5A, -l2V/100mA stabilized power supply circuit is shown. Wherein, + 5V, 1.5A is the main power supply. Output circuit using the transfo..
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This is a similar circuit to the above and provides a 4 LED bar graph indicating the voltage of a common 3. 6 volt Lithium - Ion recharable cell phone battery. The reference voltage is provided by a TL431 programmable voltage source which is set to 3. 9....
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This is a false capture circuit or Lie detector circuit. The basic principle of the resistance of human skin. While dry skin is a resistance of about 1 Mega ohm....
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This modification is to be done AT YOUR OWN RISK and there is no guarantee that the modification will work for you. Failure to properly install this design correctly may result in damage to you and/or your laserdisc player. This web site takes no....
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It is a total of four kinds of specifications. Three-phase bridge rectifier circuit. The output voltage from the regulator TY regulation...
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Using the fact that the VRE of a transistor shifts 59.16 mV per decade of current at 25°C. This cons..
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Digital ICs and opto-isolators provide the drive for this TMOS servo amplifier, resulting in fewer analog circuits and less drift. Fast and consistent turn-on and turn-off characteristics also enable accurate analog output results directly from the digital....
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This is scircuit which I built to one of audio amplifier projects to control the speaker output relay. The purpose of this circuit is to control the relay which turns on the speaker output relay in the audio amplifier. The idea of the circuit is wait around....
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A solar water heating pump controller is a key component in most solar water heating systems (DIY or otherwise). The controller is there to turn the pump on when the fluid in the solar panel is hotter than the water in the hot water tank (or swimming pool),....
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2 versions. First is one based on your schematics, except that I`ve changed those smd capacitors for standard through hole ones. Second one is somewhat modified. I`ve excluded transformer and put in standard dc jack. Also, pic and display header are located....
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This little transmitter is suitable for less demanding Doppler propagation measurements. It is designed for use on 80m, but can be easily adapted for 40m or 20m. The output is about 500mW of unmodulated carrier, with a stability of about one part in 106, or....
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One of the simplest sinewave oscillators is the Wien Bridge Oscillator. Any circuit requires 2 conditions to oscillate. Tracing the path from the input, round the feedback network, back to the input there must be an overall phase shift of 0 degrees at one....
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The count advances as the clock input becomes high (on the rising-edge). Each output Q0-Q9 goes high in turn as counting advances. For some functions (such as flash sequences) outputs may be combined using diodes. The reset input should be low (0V) for....
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A white-LED-based emergency light that offers the following advantages. 1-It is highly bright due to the use of white LEDs. 2-The light turns on automatically when mains supply fails, and turns off when mains power resumes. 3-It has its own battery charger.....
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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 detectmetal wiring if it conducting ac....
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The vertical deflection amplifier uses a 180 degree phase splitter to generate a differential signal. The CRT requires large drive voltages, but almost no current. The oscilloscope bandwidth is limited by the amplifier chain as almost all electrostatic CRTs....
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The sensor is a standard TO-5 or TO-46 package. For surface or air temperature sensing. Small clip-on heat sinks can be used. A simple probe can be made using heat-shrink tubing and RTV silicon rubber. Three-leads-plus-shield cable is a good choice for wire....
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Circuit shown in Figure 3-9. It is similar to Figure 3-8, except that zero off MOC3061 type photoelectric coupling B directly connected to control fan operation. ..
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Start-up is a stressful time for the power driver section of
a switching power supply. Because the output voltage is
initially zero, the feedback error initially jumps to its maximum.
The large feedback error then drives the loop filter
to its limit,....
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This module is an enhanced version of the D. C. mixer designed for both audio and CV mixing. It has both non-inverting (adding) and inverting (subtracting) inputs, as well as a master level control. It also features two inverting outputs, one (out2) that is....
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When configured as a free-running multivibrator, a 555 timer provides no more than a 50% duty cycle. By adding two transistors, however, you can obtain a variable 5 to 95% duty cycle without changing the sum of the on and off times. When VouT decreases,....
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This circuit utilizes an HA-5152 dual op amp and FET to produce a low-voltage, low-power, Weinbridge sine-wave oscillator. Resistors R and capacitors C control the frequency of oscillation; the FET, used as a voltage-controlled resistor, maintains the gain....
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A 4V-60V to 5V DC/DC converter is shown in Figure 2. This
converter is well suited for 12V automotive battery applications,
maintaining output voltage regulation with battery
line voltages from 4V cold crank through 60V load
dump. The threshold for....
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The Softrock Lite V6. 2 series provide an economical entry-level kit for the ham or SWL who wants to experiment with Software Defined Radio (SDR). As of 10/26/2008, the offerings in this series are (links are to schematics in Yahoo Groups files folder ):....
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Addition of diode limiter and positive feedback resistor to UAF41 universal active filtrer gives precision quadrature oseillator. -Y. J. Wong, Design a Low Cost, Low-Distortion, Precision Sine-Wave Oscillator, EDN Magazzine, Sept20, 1978, p 107 113. ..
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BTS412B as two high-side power MOSFET switch and two BU271L (50v, Zhang 1n) for the low-side switch, can be composed of bi-directional H-bridge DC motor drive circuit shown in ..
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Before getting started an acknowledgement is due, the circuit presented here uses an ingenious method of controlling a flyback converter by the voltage developed on a cur-rent sensing resistor, this was published by Andrew Armstrong in the July 1992 issue of....
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The preamplifier was designed to signal sources such as low-impedance moving coil cartridges (MC) on turntables
high fidelity (and yet still there). The impedance of the amplifier is 100 W. To keep the noise levels low, three double-type transistors MAT03....
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Let`s construct a low-power FM transmitter using surface-mount devices (SMD) that will be received with a standard FM radio. Soldering surface mounted devices is not so hard and actually is quite easy. There are many designs for small FM transmitters but....
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If 40 watts RMS from 20Hz to 30KHz +/-1. 5 db sounds good to you, then you might enjoy this experiment. The most significant problem with public address gear is the use of audio output transformers which do not have enough iron in them to handle the lower....
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After building so many Nixie Tube Clocks from the Internet, I finally decided to design my own. My clock uses IN-12 Nixie Tubes and an 8-core Propeller Microcontroller. The Propeller may a be a bit of overkill for the task, but it`s the microcontroller that....
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As we all know, if the power transformer neutral line circuit, and when the three-phase unbalanced load and can easily lead to electrical equipment (such as household appliance..
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Modify a zapper circuit (like the Hulda Clark Zapper) to get two differente frequencies. One switch to make the pulse to 15Hz and the other to 30. 000Hz. The nominal frequency for that circuit is 35kHz (35, 000 Hz), not 30 Hz. You can cut the frequency in....
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Circuits that use a temperature compensating resistor have a small error because the tempco`s resistance is a function of temperature T, rather than 1/T as is theoretically perfect. The fact that tempco circuits are de-riguer attests that this remaining....
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The special feature of the circuit shown below is the low consumption. With voltage n 9 at the entrance and no exit load, absorbs current 50 ma, which is certainly very small compared with a quiescent current 78L05. The components that comprise it are....
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This is a 8048/IM80C48 Microcomputer with 8 character 16-segment ASCII triplex liquid crystal display. The two bit character address is merged with the data and written to the display driver under the control of the WR line.
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This turned out to be quite an interesting project. It all began as a project for a paying customer, but I found that the circuit had quite a lot of advantages over previous similar projects. It is basically an inverter for converting power from 12v DC to....
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The GB4551 is a high performance video buffer with DC
restore primarily used for accurate back porch clamping.
The circuit features a wideband differential amplifier that
can be configured as a gain stage. The output signal
voltage is limited to +2V....
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For this simple lead acid battery charger we need a center tapped transformer (12V 0V 12V) which need to give a 5 amperes current, two diodes and one capacitor. To charge the batteries we need to connect the terminal + and - from the charger to the same....
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This project illustrates how to use an ATTiny microcontroller and an RGB LED to create a coloured light that cyles continuously through random colours, but changes colour dramatically at the press of a switch. Why My kids had this $2 novelty pen that did....
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The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders"74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate....
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The values of LM56 Thermostat project Circuit diagram of R1, R2 and R3 for the points of travel, VT1 and VT2 can be determined using the subsequent equations. This thermostat of electronic circuit with IC LM56 diagram what simple project, you can use as....
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The metal detector circuit is composed of the probe oscillator, PLL phase-locked loop circuit and the audio alarm circuit, and the circuit is shown as the chart. Probe oscillator is composed of the detection coil L, transistor VI, resistors RI ~ R3,....
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As shown for the LM4911 different power conduction time recommended circuit. This circuit uses a controller, use the controller of the MOSFET LM4911 shutdown control (SD) termi..
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The AB763 Super Reverb is a very popularFender ampdue to the huge tone, robustness and the pure tone from the traditional blackface AB763 amp design. The AB763 design is alsoto be foundin some silverface amps between 1967 and 1969. The later silverface....
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A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperature (of about 600 degrees Celsius!) the lambda probe supplies an output voltage proportional to the amount....
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48 V ‘phantom powering has become the standard for professional condenser microphones. The supply (or rather bias) voltage is applied over both wires of....
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This program uses an 8 bit DAC along with a 16F84 PIC microcontroller to generate a keyed sine wave. The 16F84 uses an RC clock which can be varied (with a suitable potentiometer) to allow a variable frequency control for the sine wave output. A key or keyer....
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FIG, M is a variable speed motor control wicket opening and closing and opening. O electric governor. Front grid, hit the power switch SA A side, toggle switch S is opened; aft..
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Switching diodes are used to fire the neon lamps when negative-peak modulation hits 50. 60, and 100%. To use the circuit, keep an eye on the lamps. ..
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Fuse Cum Power Failure Indicator employs thermister and timer IC NE555 circuit diagram with parts list of fuse cum power failure indicator indicate power failure...
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Generating variable audio frequencies with crystal precision is not often done because it isn`t easy to make. Low frequency quartz crystals are difficult to find, and each would only provide a singular frequency. Some small tweaking of the crystal....
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This pdf file shows the schematic diagram of my home-built circuit to drive the PDR-56 probe. A JKL BXA-12579 inverter commonly used to drive cold-cathode fluorescent lamps is used as the high-voltage power supply. The BXA-12579 produces 1, 500 VACRMS for a....
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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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This circuit enables observation of movement between other stroboscopes. Generation of rectangular signal is based on NE555. This circuit requires a low power supply that is made from a simple transformer TR1, traditional rectifier bridge and zener diode....
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Using the software during flight simulation models of planes: REAL-FLIGHT, we first chose a housing of any transmitter empty direct connection potentiometers innings. However this is not good because, first races of the potentiometers are only 90 degrees,....
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This circuit is a simple dual simplex to half-duplex driver for 1-wire devices, although it does not work with all of them, because some draw too much current. It was designed and tested for DS18B20+ 1-wire digital thermometer. The parasite power only....
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This charger will quickly and easily charge most any lead acid battery. The charger delivers full current until the current drawn by the battery falls to 150 mA. At this time, a lower voltage is applied to finish off and keep from over charging. When the....
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This is a voltage controller oscillator that was designed as a wide range oscillator to generate clock pulses for a stepper motor drive system. It does however have some interesting features. The original application used a stepper motor for its ability to....
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SCRs are unidirectional (one-way) current devices, making them useful for controlling DC only. If two SCRs are joined in back-to-back parallel fashion ....
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This is a very good integrated circuit. There is no need for any external glue logic to drive the circuit, there is only 2 pins to drive the motor, one for controlling the direction and the other to trigger the stepping pulses. It provides a very compact....
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My wife was working on a doctoral dissertation and needed to do some field work involving personal interviews in various settings. What would be the best way, technically speaking, to record the interviews To pass a tape recorder or microphone back and forth....
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Fixed-value capacitors are disc ceramics. CI, C4, C5, C6, and C8 are NPO ceramic or polystyrene. C2 is a 25-pF ceramic trimmer and C3 is a 15- pF miniature air variable capacitor. The resistors are -W carbon film or composition. The RF chokes are miniature....
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Well since I learn fastest by doing (not exactly unique I guess) time to start my next trick. Adapting one of the many curve tracer schematics, probably Metzger`s circuit from the early `70s with modifications to an ADC capture system and output to a 320*256....
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In this circuit the 555 Timer IC is connected as a astable multivibator and a 12 volt relay is derived through the pin 3 of the IC. The IC generates continues pulses at pin 3 which will activate and deactivate or flash the relay accordingly. The flashing....
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This is a simplified version of the 4-Digit Keypad Controlled Switch. I have modified the design to reduce the complexity of the circuit - and the number of components required. As a result - the code is somewhat less secure. However, there should be lots of....
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LA4440 is a two channel audio power amplifier IC with inbuilt in dual channels enables it for stereo and bridge amplifier applications. In dual mode it giv....