Popular Circuits Page 177
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Provides timing in seconds to 99 s, and timing in minutes to 99 min, with 2-digit LED indicator showing elapsed time. Desired interval is set with BCD thumbwheel switches. LED readout counts up to preset time, then resets automatically to zero. Switch giving....
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I have also realised that my intentions for night air charging are possible, but unnecessary. When heating is going on (late March/early April) the boxes worked at night because air temp was better than glycol temp - that was helpful. Now that it is summer....
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Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. Such a circuit is very useful in automobile subwoofer applications. The circuit is nothing but a low pass filter whose pass frequency can be adjusted between....
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The greatest sensitivity is achieved if R1 is approximately equal to the probe resistance. The circuit can be zeroed with R2, while the full-scale voltage is controlled by R5. The correlation between pH and output voltage might not be linear, which would....
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A simple electronic circuit project is discussed here that may be built by any school student for displaying in a school fair science exhibition. The proposed circuit is a high gain opamp amplifier which detects slightest of RF disturbance that might be....
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This circuit, enclosed in a small plastic box, can be placed into a bag or handbag. A small magnet is placed close to the reed switch and connected to the hand or the clothes of the person carrying the bag by means of a tiny cord. If the bag is snatched....
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The two basic parts for working with IR are the emitter and the detector. The emitter is typically an LED that emits near-infrared light. A typical wavelength is 880nm, which is just beyond the human eyes ability to see. Many suppliers, new and surplus, can....
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I used 45 peices of 220 ohm resisters to make 10k ohm variable resister. By banding the wire of the resister I made hook to sew it through. If you want even less volume than normal resister, you can use tiny surface mount resister. To tie with the thread,....
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Audio Visual Ringer. Many a times one needs an extra telephone ringer in an ad-joining room to know if there is an incoming call. For example, if the telephone is installed in...
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This circuit is sensitive to low frequency electromagnetic radiation and will detect for example hidden wiring or the field that encompasses a transformer. Pickup is by a radial type inductor, used as a probe which responds well to low frequency changing....
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A Pierce (crystal) oscillator intended to provide a reliable clock signal for at least 1 year when powered by battery voltages as low as 2.4 V..
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There are 4 timers in PIC18 which are timer0 to timer3. Timers are used when precise timing event need to be generated. Timers are usually used in conjunction with interrupt to keep the timing accurate. This guide will show an example of using timer0 to....
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When the phone rings, the ring signal from the telephone company lights a neon lamp within a CLM3120 optocoupler. That causes a drop in the resistance of the CdS cell output of the device, turning on transistor Ql. ..
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Three lights are controlled by the three channels. One light will pulse in response to the bass, another illuminates with mid-range sounds, and the last lights for high notes. Four level controls allow adjustment of overall light level and each channel....
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This is a 4 digit decimal counter which can operate as a free running counter or in count and hold mode with manual reset. In either mode the counter can be preset to count to a specified value. Clock edge and leading zero suppression can also be....
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This application note describes a complete flyback switched
mode power supply that uses a Fairchild Power Switch. The
MOSFET and its control IC are built into one package. The
MOSFET is in fact a SenseFET. Various protection features
are also included.....
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As can be seen from the circuit loop, the circuit is mainly two times a Butterworth filter, in order to make a 0.707, magnification feedback amplifier d was d 3- (1/Q) 1. 5860 ..
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The "green area" is where should be placed the TRF7970A `s antenna (Between 0 ohm resistors, the antenna should be connected). TRF7970A `s antenna can be done step by step according to the document "Antenna Matching for the TRF7960 RFID Reader (SLOA135) ".....
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Today, it is by far the most common preamp tube used for electric guitar amplification and there is an almost overwhelming supply of current production options to choose from. The purpose of this comparison is simply to provide guitar players with a frame of....
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This analyst is, a sensitive instrument, in the frequency changes and width of a acoustic signal. Thus the brightness of LED that turns on each moment of is proportional signal width, while the colour of proportionally frequency. The circuit input....
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This system contains an IR transmitter, an IR receiver/RF transmitter, and an RF receiver/alert beeper. Two IR ..
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This probe is useful for any low level RF work, and simply connects to your multimeter. The voltage shown will not be accurate, since this is a rectifier probe, but the measurements are good enough for you to be able to determine where the RF stops, or if a....
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Nowadays a lot of intercom units are equipped with video cameras so that you can see as well as hear who is at the door. Unfortunately, the camera lens is....
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A shift register works by shifting data to the right with each clock pulse. Regardless of if the data is loaded in all at once via parallel load or one bit at a time via serial input. Each clock pulse shifts data into the first flip flop, the data that was....
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After I built my KN-Q7 kitset 40m QRP single sideband (SSB) transceiver, described elsewhere on this site, I went on to build a matching low power "Z-match" antenna tuner and a sensitive SWR meter. For some reason, I found I needed three hands to tune this....
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The heart of this controller is a switch mode voltage converter. L1 converts voltage. Q1 is the switch that control current the goes through L1. The b....
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At the heart of this simple circuit is the well-known type KTY10 temperature sensor from Siemens. This silicon sensor is essentially a temperature-dependent resistor that is connected as one arm in a bridge circuit here. Preset PI functions to balance the....
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Below is a circuit diagram of the motor winding current imbalance drying: ..
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12V voltage instability, you should first check the switching power supply output section, as shown in FIG. The secondary winding of the..
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The circuit as shown in the figure employs 14 bi-colour (red and green) LEDs having three terminals each. Different dancing colour patterns are produced using this circuit since each LED can produce three different colours. The middle terminal (pin 2) of the....
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The way an engine management system monitors its Air / Fuel ratio is through the Oxygen Sensor (O2) stuck in the hot exhaust flow, usually before the catalytic converter. All O2 sensors are basically the same, with some being heated or others providing....
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The following diagram is the 50W offline switching power supply circuit design. The circuit powered by a MOSFET. BUZ80A/IXTP4N8 for 220V AC voltage input and GE IRF823 for 110V AC input voltage. The output will be 5VDC with electric current up to 10A. The....
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So you`ve read about my Computerized Room or have seen those nifty home automation products advertised in the back of electronics magazines Or perhaps someone you know has done something similar. At any rate, you have decided to try it yourself. The first....
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A beautiful diy gsm jammer or mobile cell phone jammer schematic diagram for use only in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 mobile phone network is used by USA, Canada and most of the countries in South America. This cell phone....
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Mark builds and tests the DIY Moving Magnet (MM) Phono Preamplifier Kit that was featured in Silicon Chip Magazine, August 2006. The kit comes complete with everything you need except for an enclosure and a power supply (AC walwart). ...
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It will supply 15 watts of AC power to a device. It should power lamps, shavers, small stereos and small appliances. If you draw to much power the circuit will shut down all by itself. The output of this circuit is a square wave so there may be some....
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Frequency range is 100-108 MHz. The circuit is only mono circuit, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity is 5mV and the max input signal is 10mV. The transmitted signal can be....
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This circuit generates a tone that sounds very similar to a siren. The generator part of the circuit is made of the combination of PNP and NPN transistors. Toghether, the two transistors build up a free runing multivibrator. If the C2 capacitor was connected....
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As shown in FIG constituted by ISO102 OPA27 500VDV DC current measurement circuit. Circuit between + 500V DC voltage source and the sampling resistor in series with a DC motor,..
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This is digital clock schematic diagram. This circuit is quite complex and quite difficult for a newbie because this circuit uses IC with some a complicated connections. The voltages that supplied to the circuit are divided in two lines. The voltage +5VA....
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In this circuit SP6126 is configured as a Zeta converter to provide 0. 3A for driving four series-connected LEDs The SP6126 is a flexible and economical controller that provides the necessary functions required by a Zeta Regulator This report includes the....
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This LM3909 circuit produces a rapidly rising wail upon pressing the button, and a slower "coasting down" sound upon release. If it is desirable to have the tone stop sometime after the button is released, an 18-k © resistor can be placed between pins 8 and....
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In the circuit, 60 individual LEDs are used to indicate the minutes of a clock and 12 LEDs indicate hours. The power supply and time base circuitry is the same as described in the 28 LED clock circuit above. The minutes section of the clock is comprised of....
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The first BC109C transistor (left hand side) is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio....
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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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The circuit in Figure 1 is a simple, economic, compact, and tricky way of using the LM723 as a programmable voltage source to drive dc micromotors. Because of the µPs` accurate positioning and control, these motors are useful in applications such as optical....
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schematic diagram. A presentation of the element-by-element relationship of all parts of a system....
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LM4782 uses the system of protection of National Self Peak Instantaneous Temperature ( Ke) (SPiKeTM). Spike protects the exit of the lm4782 of on tension on load, short of the source for gnd, temperature protection and picks instantaneous of temperature.....
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There is a small power supply on the board for generating 3. 3V @ 250mA. We don`t use the `built in` 3. 3v regulator on the Arduino because its only guaranteed up to 50mA and some SD card need a lot of power when writing. This supply is nice and steady, we....
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Most people don`t know it, but there are usually over a dozen, battery backup systems in your home already. The average American around 18 battery backed up devices in their home. These battery backup systems backup the crucial, expensive, or mobile....
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As shown by PGA204 / 205 to the shield drive circuit of FIG. As evidenced by the interference theory and practice, the cable shield weak signal transmission with a certain potential, ..
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The timer circuit shown gives independent control of the output"s on and off intervals, which can range from 0.055 seconds to 30 minutes, relatively unaffected by power-line transients. IC1 is a CMOS programmable-timer chip that includes 24 ripple-binary....
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The BA1404 fm stereo modulator Ic contains all parts needed to design an simple high efficiency stereo transmitter circuit, it contains a stereo modulator that creates stereo composites signals, an FM modulator that creates FM signals and a RF amplifier. The....
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This circuit is intended to signal when a plant needs water. A LED flashes at a low rate when the ground in the flower-pot is too dry, turning off when the moisture level is increasing. Adjusting R2 will allow the user to adapt the sensitivity of the circuit....
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The GM Counter Accessory is shown below. It can generate a DC voltage upto 1 KV using the 5V pulse generated on PWG. The duty cycle of the pulse is varied to control the voltage. The high voltage applied to the GM tube is divided by 200 and connected to CH0....
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However effective a domestic alarm system may be, it`s invariably better if it never goes off, and the best way to ensure this is to make potential burglars think the premises are occupied. Indeed, unless you own old masters or objects of great value likely....
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This versatile amplifier circuit is designed and submitted by Mr Seetharaman Subramanian from Chennai. The full credit of this article goes to him and we are very proud to publish this fabulous circuit here. This concept has appeared long back in Practical....
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The wide diversity of automotive motor-drivers, including those used for HVAC (heating, ventilation, and air conditioning), headlamp, seat positioning, window, and mirror applications, requires circuits that do more than just switch the motor on and off. The....
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The picture shows the proximity switch circuit composed of the HMC1001 and operational amplifier (AMP04) and light emitting diode (LED). The operational amplifier is used as a comparator here. If taking a magnet with length about 6mm~12mm to close to the....
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The positive and negative peak amplitude is controllable to an accuracy of about ± 0.01 V by a dc input. Also, the output frequency and symmetry are easily adjustable. The oscillator consists of an integrator and two comparators—one comparator sets the....
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When using an analog meter to set the output of a power supply used for testing 12-volt equipment, an expanded voltmeter scale has a decided advantage and accuracy over a linear scale. Figure 1 shows the original meter scale and the expanded scale used in....
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This section serves to strengthen the signal until the signal level is required. IF amplifier is equipped with AGC (Automatic Gain Controller) which controls the strengthening of the IF amplifier so that a constant amplitude output video. Amplifier frequency....
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The screen that we watch TV on at home has build-in speakers, but, because it`s actually a computer display, hasn`t got an infrared receiver. This made it impossible to set the volume with the TV receiver remote. I recently bought some Stellaris LaunchPad....
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The precision audio-frequency-generator consists of several sub circuitsan audio-amplifier/filter circuit, an automatic level control, a variable voltage-controlled oscillator, a frequency divider circuit, an integrator, and an audio output amplifier. An....
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This is a circuit to use a standard, low quality opto isolator to transfer an analogue signal with reasonable linearity and without complicated feedback loops to monitor and linearise it. The circuit was designed to interface a mains driven thryristor motor....
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This is a stereo amplifier circuit diagram. The amplifier will produce stereo output channel with the power audio output can reach up to 70W for each channel. The amplifier built based great amplifier chip STA550 from STMicroelectronics. Take a note that....
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Here is a simple mains power failure alarm/detector circuit that produces an alarm whenever the mains supply fails. Lot of such circuits are available, but the peculiarity of this circuit is that it requires no back up power source like a battery to power....
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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 Transistor is an electronic component which enables a small current to control a much larger current. This feature is very useful in many renewable energy projects and other applications. Click here to read our Introduction to Transistors. Pictured below....
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This project is intended for controlling mains powered disco lighting, although there are many other possible uses for controlling almost any mains appliance. It will control five seperate channels at up to 3 Amp per channel. This could be increased by....
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Circuit for the principle: The alarm circuit consists of two parts, the transmitter and receiver. Figure a shows the transmitter circuit, GT is a smoke break reed switch, usual..
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Description: designed to the provide information regarding the vehicles wiring content the Toyota Tercel 1996. Component: intake air temperature sensor, ....
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motor control, energy efficiency of inverter (AC drive) selection and parameters setting guidance in mine industry: vector control, open loop or closed loop control, with energy braking unit or energy feedback unit....
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This is a 0 - 6 MHz DDS VFO controlled by a PIC16F84 (or `C84).
The VFO is separated into two modules, the DDS module and
the controller module. The PCB layout (double sided) for
the DDS module is included as two Postscript files
(scale 1:1). The .PS....
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The schematic herein appears a 5A H-Bridge Module for the working of one Bipolar DC motor. H-Bridge Module consists of one set header (J2) and one set connector terminal (J1). And here are the J2 pinout description of H-Bridge module interface:...
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The circuit depicted is the receiver device of a transmitter/receiver combination that will prove extremely handy when tracing the path of electrical wiring in a building or to locate a break in a wire. The corresponding transmitter may be found elsewhere in....
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Design a 32kHz wide supply range oscillator with a low-power comparator, a reference and crystal oscillator....
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We can use UBA2021 for 600 V lamp controller and half-bridge driver IC for high-power. The UBA2021 is a long-life CFL/TL applications. It`s equipped with....
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A digital micro-ohm meter is necessary to verify the condition of shunts used in the Electrochemical Analysis & Diagnostics Laboratory (EADL) at Argonne National Laboratories. A shunt is basically a small resistor. They are used to measure current. The....
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This is a low cost 150 watt amplifier circuit with diagram and schematic design using two darlington power transistors tip 142 and tip 147. this amplifier circuit can This is a low cost 150 Watt amplifier circuit with diagram and schematic design using two....
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The circuit of the Celsius thermometer in the diagram is based on the well-known Type LM334 from National Semiconductor. This IC is a sensor that provides a current which is directly proportional to the temperature in kelvin (K). Unfortunately, this is 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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A block diagram and a schematic of the receiver are shown in Figures 2 and 3, respectively. In Figure 3, L6 and L7 are spaced 0.6 inch for a loss of about 0.5 dB. Q4 is the first RF amplifier. L9 and L10 are spaced about 0.8 inch with a partial shield....
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The three-channel amplifier output distribution uses a single TL084. The first step is to capacitive coupling with a p. 1.0 ~ electrolytic capacitor. The entries are railways Vee Y2 or 4.5 V. This allows using a single 9 V power supply A voltage gain of 10....
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This ultra-bright white LED lamp works on 230V AC with minimal power consumption. It can be used to illuminate VU meters, SWR meters, etc. Ultra-bright LEDs available in the market cost Rs 8 to 15. These LEDs emit a 1000-6000mCd bright white light like....
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My neighbor`s drill charger stopped working. I found that the primary wires in the transformer were non-functional. This charger had a very simple design. It used a transformer, followed by a diode bridge and a larger resistor. The power supply indicated it....
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This improved infrared detector is specifically intended for use with commercial IR remote control handsets. This little circuit is useful for quick go/no-....
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You can use an ADT7461 single-channel temperature monitor; an ADG708 low-voltage, low-leakage CMOS 8-to-1 multiplexer; and three standard 2N3906 pnp transistors to measure the temperature of three separate remote thermal zones (Figure 1). Multiplexers have....
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This is the construction guide for the 5301 wideband fuel mixture display kit. The 5301 is the Tech Edge version (rather than the Jaycar version) of the modified Silicon Chip FMD design, and it features, compared to the original kit, double sided PCBs a new....
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An LM311 comparator converts a small analog signal to a digital level for the DC4046 phase-locked loop, which is configured as a first-order FM demodulator. This demodulator works with a 50-kHz FM modulated input signal. It has applications in FM light beam....