New Circuits Page 254
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It is quite easy to get a watt or more with very simple equipment, but to get more than 5 watts becomes a little more difficult. This article describes a 10 watt linear amplifier that is capable of delivering over 15 watts into 50 ohms and uses cheap plastic....
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This converter also requires either a transformer or two inductors in place of the single inductor that most dc/dc converters require. You might overlook an alternative approach because the converter uses a linear regulator and takes an efficiency hit when....
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The talking Yoda head consists of a Yoda mask and a microcontroller system to achieve the desired operation/effect. The basic operation of the project was specified as follows: The head was to be placed inside a closed box. Upon opening the box, the light....
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This circuit responds quickly enough to prevent damage from most overloads. C 1 "s input is connected to the output of the LT1088 servo circuit. If the LT1088 circuit"s output exceeds the threshold at Cl"s other input, C1 trips, discharging the 2-!"F....
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If you want to build one yourself, you have to get two audio transformers which have 1:1 transformation ratio and greater than 1 kohm impedance. There are high quality audio transformers in the markes that meet those specs, but those can be quite expensive.....
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The time circuit can provide a time delay of up to 20 minutes. The circuit is a standard relaxation oscillator with a FET current source in which resistor Rl is used to provide reverse bias on the gate-to-source of the JFET. This turns the JFET off and....
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The ac line power is brought back into the circuit through Fl, a protective 5-A fuse. One side of the ac line is connected to one side of each ac outlet. The other side of the ac line is connected to each SGR or silicon-controlled rectifier. Each SCR is, in....
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In my opinion that is the best buildable high power amplifier out there. Quality of sound is just remarkable. This is a real bomb proof amplifier like the best Valve amps. Power supply circuit is also shown. Now lets see why we are going to use MOSFETS.....
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This circuit provides 16 watts of amplification. it is built using two LM383 power audio amplifiers. use suitable heat sinks with the ic`s...
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The circuit is very simple and incorporates darlington output transistors that will provide more than enough output current than is needed to drive a 3-ohm speaker. The gain may be pre-set for a variety of input levels, making it suitable for amplifying....
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This is a very sensitive 50Mc converter allowing you to receive the entire "Magic Band" (50Mc...52Mc) on your general coverage receiver (28Mc...30Mc). It receives all types of modulated transmissions. It all depends on the receiver used. I`ve tested this....
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Peak reading meters, popular in Europe for years, are just now coming into greater favor in America, and for good reason. The main purpose for having a VU meter is obviously to monitor signal levels going to a tape recorder, reverb unit, or some other....
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Forget to turn off the ceiling fan in your bathroom? Install the simple timer in Figure 1. It`s located out-of-sight in the fan unit, and you turn it on via the wall switch. The circuit costs virtually nothing, using "junk" parts. When ac power appears, a....
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For designers of radar or sonar echo-ranging systems, an echo imitator can ease development and adjustment chores by generating a controllable pulse that's similar to an incoming echo signal. A decade ago, you'd probably use several 555 timers and their....
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The super LED flasher is actually two complete LED flasher circuits on one circuit board. The first, LED flasher is made up of 1C1 and LEDs D1 and D2. IC1 is a 555 timer IC configured as an astable (free-running) multivibrator with its output on pin 3. The....
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Simplified circuit diagram of the two-stage Colpitts
oscillator. In comparison with the classical single-transistor
Colpitts oscillator [1,2,5] the two-stage modification
includes an extra transistor Q2 and an extra capacitor C3.
We note that both....
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The transmitter runs on only 3V whereas most others run on more voltage. This dirt cheap item uses non-adjustable inductors so it is not possible to tweak for higher output. The common TX2B chip is manufactured by HIGHLAND (SHENZHEN) ELECTRONICS CO LTD and....
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This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The receiver circuit is based on the Radio Shack infrared receiver module (MOD), part number 276-137. It is also available from some of the other sources listed on....
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A digital storage oscilloscope (DSO) is a very important
piece of test equipment that can do the jobs that a normal CRO
just can`t handle. Such as capturing single shot and widely
spaced waveshapes, and looking at non repetitive....
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The versatile 5 pin L200C regulator offers both voltage and current regulation in a single package. The IC also features thermal shutdown and input over voltage protection up to 60 Vdc. The package is also available as L200CV which has straight pins for....
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This electronic pressure gauge uses a Wheatstone bridge-type pressure sensor tb drive a 3 A digit A/D converter and a display. IC1 is a pump (quad) that interfaces the bridge sensor to the A/D converter. R16 provides zero adjustment and R6 provides....
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The circuit in Figure 1 is an FPGA-based, synchronous FIFO that uses the same clock for read and write operations. The circuit can generate FIFO-occupancy flags with a minimum of logic. The boxed area in Figure 1 shows a more conventional occupancy meter.....
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The switcher output goes to the single vertical input of the scope, and a sync line from one of the inputs is taken to the scope's external-sync input. Frequency response of the input amplifiers is 300 kHz over the range of the gain controls. ..
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This ZIP file contains information about building a small radio transmitter, which has a PCB 1.75" x 2.5" (45mm x 68 mm) and has a range of about 30 yards or so. The documentation with the circuit says the freq range is 100-108 MHz, but I have found it to be....
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A block diagram of the stereo-TV decoder is shown in A. It shows the overall relationships between the separate sections of the circuit; through show the details of each subsection. The decoder section centers around TCI, a standard 4.5-MHz audio....
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The pin 3 output of the 566 can be used to provide different charge and discharge currents for Cl so that a sawtooth output is available at pin 4 and a pulse at pin 3. The pnp transistor should be well saturated to preserve good temperature stability. The....
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The fins were added to a simple flat aluminium panel, and are made from 20 x 20 x 3mm aluminium angle. Their purpose is threefold - they improve the performance of the plate as a heatsink (although this is not necessary with the BP4078 PWM amp), they make....
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In recent years, following CD`s introduction, vinyl recordings are almost disappeared. Nevertheless, a phone preamplifier is still useful for listening old vinyl discs from a well preserved collection. This simple but efficient circuit devised for cheap....
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The circuit is based on the known chip TDA1524, which is an integrated control Volume, Bass, treble, and Balance. These arrangements are made through 4 potentiometers (P5-P8) with trend. The integrated circuit IC1, to run the needed very few external....
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The power bandwidth of the HA-5147 extends the circuit"s frequency range to approximately 500 kHz. R, can be made adjustable to vary the frequency ifdesired. Any timing errors because of Vas or hu., have been minimized by the precision characteristics....
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This circuit emits a beep and/or illuminates a LED when someone touches the door-handle from the outside. The alarm will sound until the circuit will be switched-off. The entire circuit is enclosed in a small plastic or wooden box and should be hanged-up to....
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This self-build project can simulate a telephone call / connection between any two local telephone devices. This for a fraction of the outlay of some commercial units, many with cost-increasing features that usually are not required. The circuit is centred....
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The headlight flasher is nothing more than a 555 oscillator/timer that`s configured as an astable multivibrator (oscillator). Its input is used to drive the gate of an IRF53IND hexFET, which, in turn, acts like an on/off switch, ..
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This circuit uses a positive-feedback loop closed around~a combined comparator and integrator. When power is applied, the output of the comparator will switch to one of two states, to the maximum positive or maximum negative voltage. This applies a peak....
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This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover the medium waveband from about 550Khz to 1650Khz. The tuning voltage is supplieb via RV2, a 10k potentiometer connected to the 12 Volt power....
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A 7805 can be configured as a constant-current regulator, to serve as an inrush current limiter. Rl will have 5 V across it at all times so the total current through 11 will be 5 V/R1 + 5 mA, the 5 mA being the regulator operating current...
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A ground loop in your AV system caused by antenna connection or TV cable is very common if you have your computer connected to the same system. This type of ground loop problem can be solved by using suitable isolation between your AV system and the antenna....
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You use a frequency discriminator to compare one signal frequency with another one. A functional feature, retriggering, of a monostable, one-shot 74xx123 multivibrator can yield frequency discrimination. Figure 1 shows a frequency discriminator that....
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This circuit is based upon the change of frequency of the function generator with the input voltage ViN· Generally, the frequency depends upon the capacitance and resistor connected to pin 6. This resistor is replaced by the FET. ..
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This is a schematic and block diagram of a 2-MHz frequency counter. It uses and LSI counter/display driver, LCD readout, and a few logic chips for timebase and timing pulse circuitry. Q2 and Q3 form a signal (input) amplifier. The circuit contains a crystal....
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A medium power amplifier that is characterized by a lot of good sound quality, but simultaneously is very simple in the construction. Him uses, enough time in my active loudspeakers. In his output stage exist the very good FET transistors, technology....
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Figure 39-2"s circuit combines a low-noise op amp, IC1, with a chopper-based carrier-modulation scheme to ..
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For the 60W amplifier, a nominal (full load) supply of +/- 35V is required, so a 25-0-25 secondary is ideal - however, see Updates, below. The circuit for the supply is shown below, and uses separate rectifiers, capacitors and fuses for each channel. Only....
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The SPC2 is a solar power center, it can be used to handle all of the power functions for small 12 Volt solar powered devices. It contains a photovoltaic charge controller and a low voltage load disconnect circuit. The low voltage disconnect has a load....
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Efficiency can be increased by using a germanium transistor at the 33 ohm current sense resistor, and by using a proper torroid core in place of the crappy ferrite bead. Single AA cell powers two LEDs at constant current....
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Intelligently modifying the motor-drive commands to a robot can give you control finesse during competitions. Moving a joystick hard right, for example, might have different effects, depending on the robot`s speed and direction. Software running on an....
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Early DACs contained standard R-2R ladder networks, and produced a negative output voltage. These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output. With the transition....
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This circuit can be used for multiple cameras with one monitor. The circuit can be operated manually or automatically...
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A wideband high gain configuration using two SL550s connected in series. The first stage is connected in common emitter configuration, the second stage is a common base circuit. Stable gains of up to 65 dB can be achieved by the proper choice of Rl and R2..
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Resistor R1, capacitor C1, and two converters form a square wave generator, which produces the basic tone. The generator is sui followed by an inverter which serves as both a buffer and a driver for the President. The resistor R2, which has a minimum value....
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That`s right, Electric is open source! You can download Electric from the web for free.There is no better way to get to know a CAD system than to use it for a while. Now you can use it at no charge! If you like it, keep it! If you don`t, you`ve lost....
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This Circuit shows the GT4122 used as a two input video mixer.
An evaluation PC board has been made and the artwork is
included. Using this circuit, many of the critical circuit
parameters can be measured including Crossfade Balance,
Linearity,....
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A functional block diagram is shown below and illustrates
the primary circuit functions. These include equalization,
reclocking, and driving 75W co-axial cables. A complete
schematic is also included.
The EB-RD35 accepts a serial digital data input....
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The genesis for this hybrid electrostatic headphone amplifier occurred when I was in Hawaii on vacation, at a fancy hotel on Maui. Sitting at the bar on the beach, drinking "Blue Hawaiis," I drew the schematic for the amp on a placemat. The design is my....
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This circuit shows a method which increases the power capability of a drive system for audio speakers. Two HA-2542s are used to operate on half cycles only, which greatly increases their power handling capability. Bridging the speaker, as shown, makes 200 mA....
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The preamplifier that appears in the figure is a completely symmetrical preamplifier, from the input as the exit and it works in Class A. It does not have somebody innovation, simply it uses good solutions, in order the result is what should. Such proposal....
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The new LTC1155 Dual Power MOSFET Driver delivers
12V of gate drive to two N-channel power MOSFETs
when powered from a 5V supply with no external
components required. This ability, coupled with its
micropower current demands and protection features,....
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It is a voltage regulator that allows a 6v portable supply to be derived from the 12v car battery. You can add a 6.2V zener diode and a LED to warn you when the input supply is overvoltage. If you could find a relay that would operate from 6.2v right up to....
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This is a very easy and fun to build project that will allow you to control up to eight external devices through your computer`s parallel port. You may for instance control different appliances such as lamps, computers, printers, tv sets, radios, music....
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Care must be taken to eliminate any stray currents from flowing into the current summing node. This can be accomplished by forcing all points surrounding the input to the same potential as the input. In this case the potential of the input is at virtual....
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A Coil Coupled Operation Metal Detector made from readily obtainable components and using an ordinary medium receiver as a detector. The metal detector shown here may well represent a new genre. At any rate, after some exposure, it is regarded as such by....
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A high speed oscillator is possible by combining an MECL 10 crystal oscillator with an MECL III frequency doubler as shown. One section of the MC10101 is connected as a 100 MHz crystal oscillator with the crystal in series with the feedback loop. The LC....
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Linear regulators are easy to implement and have better noise and drift characteristics than switching approaches. Their largest disadvantage is inefficiency: excess energy dissipated as heat. Several well-known techniques are available to minimize the....
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In its simplest form, a voice-over unit is just a microphone and change-over switch feeding an amplifier, the output from the microphone having priority over the amplifiers audio signal when the "push-to-talk" switch is pressed. In this circuit, a....
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The operation of a 303MHz circuit has been covered in our project WIRELESS DOORBELL.
We are not going over how the circuit works but explain the importance of some of the components and how they effect the range. The most critical component is the....
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Transistors Ql and Q2 form the two halves of a free-running multivibrator whose frequency is determined by the voltage across C8. That capacitor is charged and discharged by closing and openingBwitch Sl. Transistors Q3 and Q4 make up a VFO. The output of....
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This mini audio amplifier will test the audio stages in amplifiers such as the front end of FM bugs. You can also use it on lots of our other projects as well as the output stages of radios. It is a very handy piece of test equipment and will make a perfect....
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This circuit shows amplifier Al as a sensor amplifier in a bridge configuration. Amplifiers A2 and A3 are configured as a voltage to frequency converter and A4 is used as the transmitter. This entire sensor/ transmitter can be powered directly from a 4 to....
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This high-performance charger quickly charges gelled lead-acid batteries, and turns off at full charge. At first, the charg..
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The MAX6953 from Dallas Maxim is a compact cathode-row display driver that interfaces a microprocessor (like PIC or AVR) to four 5x7 dot matrix LED display trough an I2C compatible serial interface. The chip includes some features that can help us to handle....
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Section Ul-a is configured as a high-gain inverting voltage amplifier that is inductively coupled to the phone line via LI. Inductor LI is a homemade unit that consists of 250 turns of fine, enamel-coated wire that is wound on an iron core. The op amp....
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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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This design reconfigures the APD-bias IC, IC1, to allow its low-voltage DAC output to modulate the high-voltage, current-sense feedback via a high-voltage-output transconductance stage comprising Q2 and Q3. These two complementary transistors provide....
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The unit has a separate amplifier and oscillator section allowing them to be used separately if need be. The injector is a multivibrator running at 1 kHz, with R5 andR6 dividing down the output to a suitable level («1V). The tracer is a single-stage....
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A thermostat doesn't try to maintain a constant temperature. In order to do so - it would have to keep switching on and off every few seconds. Instead - it keeps the temperature within a specific range. When the preset temperature has been reached - it....
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A resistive voltage divider is used to establish a bias voltage for the input (Pins 2 and 3). The demodulated (multiplex) FM signal is fed to the input through a two-stage high-pass filter, both to effect capacitive coupling and to attenuate the strong....
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This circuit us gives the sense of movement of ball up down, after the LED turn on successively the one afterwards the other. As soon as it reaches in the one or in the other end it makes again the opposite movement to behind. As clock are used two inverters....
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The circuit, uses a two-transistor direct-coupled oscillator that has a frequency determined by CI, R2, and the (skin) resistance across the touch pads. Since CI and R2 are fixed values, only the skin resistance across the touch pads can vary the sound of....
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No description available...
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Switch programmable on/off or interval timer, has three relay-switched outputs. Output one is active for the duration of time 1, output two is active for the duration of time 2, and output three is active for the duration of both one and two. Timing data is....
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The output frequency from IC pin 3 is determined by the voltage input to pin 6. A standard frequency counter can be used to measure voltages directly over a limited range from 0 to 5 V. In this circuit, the 555 is wired as an astable multivibrator.....
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This circuit is designed primarily for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on, the circuit will trip. After a few minutes delay - when the thief is at a safe distance - the....
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The signal booster, built around a few transistors and support components, offers an RF gain of about 12 to 18 dB ..
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CMOS switches are used directly to select the entries in the audio circuits, it can introduce unacceptable levels of distortion, but if the switch is included in the feedback network of an op amp, the distortion due to the switch may be virtually eliminated.....
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The circuit is a MOSFET based linear voltage regulator with a voltage drop of as low as 60 mV at 1 ampere. Drop of a fewer millivolts is possible with better MOSFETs having lower RDS(on) resistance. The circuit in Fig. 1 uses 15V-0-15V secondary from a....
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This simple three-phase tester, uses only a small current thyristor as a main element for testing the right or wrong succession of the three phases, and there is no need for a supplementary power supply. The basic circuit is shown in Fig. 69-4A. When....
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This circuit provides 20 ±0.1 dB voltage gain from 0. 5 to 25 MHz and ± 3 dB from 70 kHz to 55 MHz. An LM733 video amplifier furnishes a low input-noise spec, 10-I"V typical, measured over a 15.7-MHz bandwidth. ..
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Modern set-top DBS TV tuners require high performance, broadband voltage control oscillator (VCO) designs at a competitive cost.To meet these goals, design engineers are challenged to create high performance, low-cost VCOs...
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The multivibrator is a common circuit that consists of an amplifier with both positive and negative feedback (Figure 1a). When the output is positive, the positive input terminal equals ½V+, and the voltage at the negative input terminal changes toward V+.....
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In an R-2R DAC design with supply voltages exceeding ±5V, large voltage glitches (up to 1.5V) can occur during the DAC`s major-carry transitions. These glitches can propagate through the output buffer amplifier and appear at output. The slewing of the level....
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This circuit will convert four-bit BCD into a variable voltage from 0-9 V in 1 V steps. The SN74141 is a Nixie driver, and has ten open-collector outputs. These are used to ground a selected point in the divider chain determined by the BCD code at the input,....
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Two combinations of cell count and output voltage are to
be strictly avoided: three cells converted to 3.3V and four
cells converted to 5V. These combinations are troublesome
because no ordinary regulator (boost, buck or linear)
can accommodate a....
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Virtually all domestic and professional dimming systems are based on triacs. These devices will conduct once they have been fired, only while current flows in excess of the holding current of the device. These dimmers work very well with a resistive load....
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This circuit can generate high-voltage pulses with an inexpensive auto ignition coil. Add a rectifier on the output and the circuit produces high-voltage de. The circuit"s input is 115 Vac. During the input"s positive half cycle, energy is stored in....
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Precision Frequency generator 1 to 999 Hz
Precision Metronome 1 to 999 beats per minute. CMos IC1 and IC2B quad AND gate form a 2.4576 MHz crystal oscillator plus a 2400 times divider. IC3A provides further division by 16, delivering a 64 Hz stable....
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The IRF820 MOSFET has a voltage rating of 500v, it should work well in preamp stages of most tube amps. The 100 ohm resistor is there to suppress H.F. oscillations. If IRF820 is physically close to the 12AX7 plate, you probably won't need it. You can see how....
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An FM radio on a single chip requiring only a few simple peripheral components. In particular the ship requires only one simple coil and alignment is very easy. The chip includes an RF input stage, mixer, local oscillator, IF amplifier/limiter, phase....
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A common need in many systems is to obtain positive and negative supplies from a single battery. Where current requirements are small, the circuit shown is a simple solution. It provides symmetrical ± output voltages, both equal to one half the input....
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Recently, I have needed to measure inductances in the hundreds of microhenries to several millihenry range. Though I have a pretty good LRC meter and an excellent bridge on my workbench in Mesa, Arizona, I wanted to make these measurements in my home in....
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By using the preamplifier with a short length of shielded cable and clip leads, signals that generally could not generate a readout, generate precise and stable readouts on the counter. The DPDT switch is used to bypass the circuit when amplification is....