Popular Circuits Page 135
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This power supply was designed for use with the Simple hybrid amp` published elsewhere in this issue. It is of course suitable for use in other applications as well. We`ve used a cascade generator for the 170 V, a switch mode supply for the 16 V, a series....
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The 40W Amp OCL 2N3055+MJ2955 is easy to build,and very inexpensive. To use Power Supply +35V -35V 2A. Transistor 2N3055+MJ2955 must be mounted on heatsink. Can....
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This is a design for sensor circuit. This circuit is using LED for sensor a light. But, for control operation and amplifier the output is using 1458 IC. This is an op-amp. This is the figure of the circuit; A circuit that is takes advantage of the....
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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 can be found in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of temperatures. If using a different....
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The 4046 PPL is used as the heart of a tunable ultrasonic receiver that can be used to locate unheard ultrasonic sounds. The receiver might also be used, along with a simple ultrasonic generator, to send and receive Morse code. The incoming ultrasonic....
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Here`s a really simple and inexpensive Power LED driver circuit...
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Designing and building a USB sound card longer a head ache got the PCM 2702 integrated circuit from Texas Instruments. The PCM2702 is an integrated bit digital to analog converter that has digital to analog output channels. The integrated interface....
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A GPS tracker demonstration program with data logging capacity. It uses BasicStamp 2P (also you can use PIC chip) to interface with a GPS Module, JP Module and 16x2 LCD display. Sample code used is standard PBasic 2. 5 ( It can be changed to PicBasic or....
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As you can see in this schematic circuit this battery charger has extreme few components, but is doing a very good job. When power is applied to the circuit the SCR1 is off, so there is no bias-current path to ground. The LM317 is connected to the battery....
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Many applications require highly efficient negative-voltage post regulators with low dropout voltage ..
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The circuit"s threshold is set by resistor R2. When the intensity of the light falling on the LDR is lowered, resistance of ..
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This is the circuit that sparked off all the other Link Telephone Intercom designs. Originally designed back in 1996 with heavy duty relays and their contact banks, it was updated late last year with the addition of IC1 in place of a simpler transistor....
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As mentioned before, a simple pulse stretcher like a 74HC123 could have been used, but I didn`t have one so I used a PIC instead I was going to dr....
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I read Doug Grant`s article regarding Heathkit in his Blog via the EDN Network. Doug reminisced about building his first Heathkit and how much he learned. He suggested that every EE had at least one kit and I suspect he is right. However, as Doug pointed....
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The ADF4252 Fractional-N Synthesizer when combined with a VCO and loop Filter forms a complete phased locked loop (PLL). This solution from ADI creates state-of-the-art LO`s (local oscillator) for the upconversion and downconversion of RF signals in Wireless....
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A novel use of solar cells makes positioning your car in the garage rather easier than old tyres, a mirror, or a chalk mark. The six solar cells in figure 1 serve as power supply and as proximity sensor. They are commercially available at relative low cost.....
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This flip-flop circuit is a free running/astable multivibrator one, with bases and collector of both emitter biased transistor are directly coupled to each other. Switching action is supported by means of capacitor in each emitter circuit. This configuration....
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The circuit includes a shift register chip (74HC595N), which I couldn`t find on CircuitLab. Is there any specific drawing to represent a shift register on a schematic I can`t help you with circuitlab, but if you just want a schematic picture, you can take a....
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This circuit uses a Cmos 4017 decade counter to create a sequence of four separate events. The number of events in the sequence may be increased to nine or ten. And the length of each event is controlled independently. You`re not limited to a series of -....
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This voltage to frequency converter circuit has an oscillator that is voltage controlled and has a small, 0. 5% deviation. IC1 function as a multivibrator and produces rectangular impulses with equal width. The output frequency can be easily adjusted with....
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What exactly is a multivibrator? I suppose one definition would be 'a circuit which has several states'. This will do for now, it's quite loose so leaves plenty to the imagination! Conventional multivibrators have only two stages and come in three flavours:....
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This simple circuit is sure to have the police beating a path to your door - however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat. The circuit transmits on Medium Wave (this is the small....
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Delay starting a motor control circuit ..
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This white led driver circuit circuit drives as many as four white LEDs in parallel from a 3. 3V source, and adjusts the total LED current from 1mA to 106mA, in 64 steps of 1dB each. To control the LED brightness, op amp U2 monitors the difference between....
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By the three current transformers Current detection signal obtained after rectification, filtering the output of the three DC voltage, are applied to the transistor VTi, VT2 an..
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The UHF motion detector operates on the Doppler radar principle. Ql is an oscillator that creates a radiated signal. An..
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His transducer is out of a humidifier and it operates at 48 Khz. It has the driver circuit too. Easy access for mods. I may have to go to walmart. From the looks of things, as I am taking apart one of the two transducers I have - They look like they`re not....
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Speaker relay delay controlling circuit for audio amplidier..
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This regulated power supply can be adjusted between a few volts and 15V with P1 and with P2 adjust the upper limit ( 15. 0V ). R6 value is 0. 7V / Imax where Imax is the maximum current. At Imax = 5A, R6 is 0. 14 © T1 and T2 must have heatsinks because power....
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VOX is a voice controlled switch, used often for microphones replacing the classic switching button. The actuating threshold is set thru the volume potenti....
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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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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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Beeper and/or LED remotely-operated via mains supply line. Pressing the pushbutton of the transmitter, a sound and/or light alert is activated in the receiver. The system uses no wiring or radio frequencies: the transmitted signal is conveyed into the mains....
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Transistor optocouplers interface circuit as described in 15.1.6 has been. Transistor interface circuit with other circuit..
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This circuit is designed to operate an electrical door-release mechanism - but it will have other applications. When you enter the four-digit code of your choice - the relay will energize for a preset time period. Use the relay contacts to power the release....
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Loop stability analysis usually starts from an open-loop Bode plot of the plant under study, e. g. the power stage of a buck or a flyback converter. From this diagram, the designer CAN extract phase and gain data within the frequency range of interest. His....
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This circuit is based on the BA5406 audio integrated circuit and also capable to provide maximum output power of 3 watts per channel . This audio ....
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The setting of delay timing of program will depend on CPU speed. You can use the timing delay on C+ library so you can set the standard timing at any computer but the minimun time delay can achieved was 1ms. It can be improved at less than milisecond by....
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A medium current switch mode power converter, designed for powering of superconducting loads requiring positive or negative current and positive or negative voltage control (4 quadrants). Constructed from a modular architecture composed of 2x [+/-400A +10V]....
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The amp appears to be unused, still has the plastic film stuck to it. One of the 211`s has a loose component rattling around inside so we will need to get one of those. As I said in my earlier post, it is the possitioning of the 6 smaller valves that we are....
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The following are detailed schematics for the QScreen Controller. The QScreen Controller combines an embedded computer based on the 68HC11 microcontroller with a touch panel and LCD (liquid crystal display) graphic user interface ( GUI ) that is ideal for....
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Video switcher circuit is needed to display more than one display in one monitor. Take a look at below circuit schematic : MAX454 is the core of this video. It is a video multiplexer-amplifier assembled by MAXIM Semiconductor. Pay attention when designing....
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This circuit is a series of electric lamps Flasher. This circuit is designed for flash bulb 12V approximately one-second per level. Base behind when Q2 Q1 provides biasing to eliminate the need for a resistor. Typically, a cold light bulb can be pulled eight....
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Dual adjustable power supply circuit with diagram using IC LM 317 and LM 337. This variable power supply circuit has a range of 1.2 Volts to 30 Volts....
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This circuit typically uses a voltage around 300 volts for the main high voltage supply and needs a low voltage supply of typically 6 to 15 volts. 555 pin connections not shown above: 1 goes to ground / negative of both low and high voltage supplies. 4,8....
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The heart of the PWM Fan Controller is a PIC 12F675 microcontroller. This microcontroller is reading the analog output of a LM35 temperature sensor using a ADC (analog to digital converter) . The resulting digital value is converted to a temperature and a....
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The basic circuit illuminates up to ten LEDs in sequence, following the rhythm of music or speech picked-up by a small microphone. The expanded version can drive up to ten strips, formed by up to five LEDs each, at 9V supply. IC1A amplifies about 100 times....
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This application note outlines the implementation of a single-supply, triangular wave oscillator using the MAX9000 and some passive components. The application circuit uses an op amp, comparator, and a voltage reference as active building blocks. The MAX9000....
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The long exposure modified TouCam Pro II camera may show signs of unacceptable noise in the pictures for exposures of over 30s or so. In order to combat this effect the CCD chip may be cooled. The cooling device I used was a Peltier module. A second hand....
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This current to voltage converter rely on the very high input impedance of the operational amplifier. The input current (I) is forced through feedback resistor (Rf), and generates an output voltage equal to (-I x Rf). This output voltage is valid for output....
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The microprocessor sends out an 8-bit binary code on its 8-bit I/O bus (the binary value needed to program the ICM7240), followed by four WRITE pulses into the CD4017B decade counter. The first pulse resets the 8-bit latch, the second strobes the binary....
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If you want to to try to make a Dashboard Digital Voltmeter Circuit Diagram including part lists, the PCB building and the placement of the components, you may download the article in full pdf here..
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Controlled by indoor and outdoor temperature, Simple, high reliability design This circuit is intended to control a heating system or central heating plan....
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The camera flashlight circuit when K1 is put through, the self-motivation oscillator composing of BG1, C1, B1 and R1 is starting to work, after being boosted by B1 and rectified by D1, it is charging C2. DW2 makes BG4 conduct when it is 5.6v, the....
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A low cost device to temporarily disable the reception of the civilian coarse acquisition (C/A) code used for the standard positioning service (SPS) on the Global Positioning System (GPS/NAVSTAR) L1 frequency of 1575. 42 MHz. This is accomplished by....
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As shown in FIG ordinary triode 3DA87C to make long-range FM transmitter circuit,..
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The circuit, built around an LM741 op amp configured as an inverting amplifier, is used to drive complementary transistors (Ql and Q2). The op amp`s feedback loop includes the base-emitter junctions of both transistorsan arrangement that helps to reduce....
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There are times when a small servo tester for modeling comes in very useful. Everybody who regularly works with servos will know several instances when such a servo tester will come in handy. The function of a servo tester is to generate a pulsing signal....
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LM134 makes a good temperature sensor because it has a highly linear output characteristic. Because it is a current output device and is therefore not affected....
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This simple QRP transceiver for the 30 m band did not result from a detailed requirement profile. I simply had some NE592 broadband amplifiers in my junk box, waiting for an application. After performing some tests, that application was quickly found: The....
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TX OpAmps TX Mixer (QSE) PTT RX Switching PA/Filters External Connectons Comments Revisions WB5RVZ SDR Home This stage adds the TX Mixer to the board and provides the modulation of the Dividers` output signals by the 4 I and Q signals from the OpAmps. The....
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The circuit described here requires no physical contact for operating the appliance. You just need to move your hand between the infrared LED (IR LED1) and the photo transistor (T1). The infrared rays transmitted by IR LED1 is detected by the photo....
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This circuit is similar to the "Fading Red Eyes" circuit (in the LED section) used to fade a pair of red LEDs. In this version, the lamps are faded by varying the duty cycle so that higher power incandescent lamps can be used without much power loss. The....
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The following describes the design, construction, operation and use of the DECL (Decade PLL) module. The module has both a Phase Locked Loop (PLL) frequency multiplier and a frequency divider to produce various output frequencies that are based on an input....
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In this circuit. a negative output voltage de-de converter generates a -5 V output at pin A. In order to generate -5 Vat point A, the primary of the transformer must fly back to a diode drop more negative than -5 V. If the transformer has a tightly coupled....
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This Circuit is a DPM or digital panel meter. It has a analog bar graph display and a 3-1/2 digit digital display. ICL7107 is used in the 200mV configuration. U4A opamp LF353 amplifies the 200mV Full scale input to the level required for the LM3914 display....
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Upper traces show voltages VOUT, lower traces show transients. Frequency transition at 500 us. Figure 16. Upper: baseband signal from simulator in FDX mode retrieved by reader. Middle: digital signal on simulator LOADMOD line that generated the upper trace.....
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Introduction: Token Display System are ideal for Banks, Airports, Public dealing offices , Hospitals , Doctors Clinics, Restaurants and other such places where people have to wait in line for Token Display System are ideal for Banks, Airports, Public....
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Simplified logic checker. Logic voltage levels have the ability to display LED (Of course I (^_^;)." H "in the LED is green," L "and red LED lights, and so both the open and goes out .
But not only that was put on the ability to detect narrow pulses. In....
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Fans can achieve remote control switch, speed control, remote control can also be achieved in other household switches. Its main feature is the use of sub-transmission side ult..
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There are no-load and short circuit protection short circuit protection. To allow time short circuit, it must increase the resistors R1 and R2 allows power dissipation, such as R1 = 1.2k Europe, 20W; R2 = 220 Europe, 4W. Technical data: Output voltage: U2 =....
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Measure voltage across the 1k resistor connected to the input stage and Vcc. The DC voltage should be about 2 volt, or 2 mA of current through this resistor. Eg, if Vcc is at 24 volts, the side of this resistor connected to the 2N5210 transisor ought to be....
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The IC is ideal for detecting the presence, absence or level of water or other conducting liquids. A detector determines the presence or absence of fluid by comparing the resistance of the fluid with the IC's internal reference resistance. An AC signal is....
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Getting microprocessor designs to work is notoriously difficult when both the software and hardware are new. The ..
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The circuit is a broad band amplifier which will take the video signals from your VCR and will amplify them sufficiently to drive up to 3 monitors, TV sets (provided that they can accept direct video signals), or other VCR ½s for recording from one video to....
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The fan runs constantly in many PCs, which may not even be necessary. A simple controller circuit can regulate the fan speed according to demand. This not only saves energy, it also reduces irritation from the fan noise. Only three components are needed to....
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H-Bridge and Half Bridge Driver IC TLE6282G Application, Dedicated for DC-brush high current motor bridges in PWM control mode and adapted for use in injector and valve applications for 12, 24 and 42V powernet applications. Useable as four fold lowside....
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Using the LTM8008 Module SEPIC converter with six post regulators can be designed a very simple compact power supply electronic project, that has six outputs that can provide different output current for some of outputs. The SEPIC controller`s fixed....
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White LEDs are popular for portable equipment LCD backlights because they are less complex, less expensive, and smaller than CCFL backlights. Portable equipment like PDAs, cellphones, and digital cameras require backlights because they are converting to....
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CJ-12 Excitation regulator is suitable for a capacity of 250kW or less automatic excitation device small generators. Its circuit is shown in Figure 7-45. Adjustment potentiomet..
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The circuit consists of the launch timer itself and an automatic-off timer. When power is applied to that IC, the countdown LED's sequence is on until they are all lit. When the last one LED1, is fully lit, transistor Ql saturates, energizing RY2. When that....
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These two circuits are SSB generators. One uses a crystal filter by KVG Electronics at 9 MHz, the other uses a 455-kHz mecha..
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The basic Idea was to have Christmas lights flash with the music. In my design I use an ordinary amplified computer speaker, a diode bridge, and a ‘CRYDOM’ SSR (Solid State Relay). In order to increase the time that the lights were on as well as protect the....
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All coils are designed using an inch diameter pvc pipe using 20 gauge insulated hookup wire, L1 require 6 turns and L2 require 14 turns. You can add turns to or subtract turns from L(or change C2) to receive other frequencies. Q2 and Q3 form an amplifier,....
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Intro & disclaimer For all you guys out there that want a fading dome light (aka courtesy light aka theatre lighting) without having to pay for....
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CH217 monolithic gas, gas gas detection alarm integrated circuits, and gas detection alarm circuit diagram R1 is the gas sensing probe, the resistance increases just gas concen..
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This is the circuit quality preamplifier with built-in USB DAC for my Leachamp power amplifier. Scheme is PCM2902 datasheet. Circuit includes DAC and ADC, SPDIF input and output of HID and with 3 buttons + MUTE, VOL-and VOL. For playback of high quality....