Top Circuits Page 22
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The oscillator section uses three sections of a 7400 quad NAND gate integrated circuit. The 1-MHz signal from the oscillator is fed into a 7 490 decade counter configured to divide by ten, providing the 100kHz signal. To obtain the 50 and 25kHz outputs,....
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The gate drive that phase controls the four parallel SCRs is accomplished with complementary MOS hex gate MC14572 and two bipolar transistors. This adjustable line-synchronized driver pennits SCR conduction from near zero to 180 degrees. A Schmitt trigger....
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This circuit for multiplying the width of incoming pulses by a factor greater or less than unity is simple to build and has the feature that the multiplying factor can be selected IYJ adjusting one potentiometer only. The multiplying factor is determined....
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The circuit doubles tbe frequency of a digital signal by operating on botb signal edges. Each transition causes exclusive-OR gate IC1 to produce a pulse, which clocks flip-flop IC3 after propagating through buffers IC2C and IC2B. Ifyou remove capacitor Cl,....
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An input signal drives both SN74 74 D-type flip-flops, which are positive edge-triggered devices. A low-to-high input signal transition triggers tbe A flip-flop, while a high-to-low input signal transition triggers the B flip-flop via tbe SN7404 inverter.....
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This circuit, shown symmetrically, divides an input by virtually any odd number. The circuit counts n + 1/2 clocks twice to achieve the desired divisor. By selecting the proper n, which is tbe decoded output of the LS161 counter, you can obtain divisors....
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The frequency doubler uses only one !C. Like other doublers, this circuit uses both the rising and falling edges of the input signals to produce digital pulses, thus effectively doubling the input"s frequency. Without the rc networks at IC1 inputs, IC1....
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Many applications require control signals that have phase shifts with reference to an input signal. Circuit accepts a sine, square, or triangular wave as an input reference signal and produces square-wave outputs with 0", 90", 180", and 270" phase shifts....
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The programmable multiple output generator provides the control signals for data converter ATE. Major performance criteria are simple, interfaces to a number of microprocessor systems, low power consumption, stable output timing relationships combined with....
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The purpose of D-type flip-flop IC2 is to synchronize the input signal with the clock pulse. When the clock pulse changes from low to high and the input is high, IC2 output is high. Subsequently, IC3 resets to zero and starts counting up. Until the counter....
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Some applications, such as driving three-state buffers for data multiplexers or for biphase clocks in high-speed systems, require complementary signals having a small-time skew and nearly simultaneous transitions. Here, XOR gates function as both....
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Two comparators and a summing amplifier that generate differential harmonic spectra comprise a simple frequency multiplier. The resulting circuit can extract harmonics from a sine, triangle, sawtooth, or any other sloping-sided waveform. With a....
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Here are two FM generators for low frequency, less than 0.5 MHz center frequency, applications. Each uses a 566 function generator as a modulation generator and a second 566 as the carrier generator. Capacitor Cl selects the modulation frequency adjustment....
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A single op amp, one fourth of an LM324 quad op amp, is configured as a standard inverting amplifier. At power up, a positive voltage is applied to the noninverting input of Ul, via R3, forcing its output high. That high output travels along three....
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This multivibrator uses a CA3420 BiMOS op amp to provide improved frequency stability. The output frequency remains essentially independent of supply voltage. Because of the inherent buffering action of pin 6, ..
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This circuit generates a symmetrical, 10-m V pk-pk triangle waveform which is summed with a de level and connected to the aid analog input for noise/DNL testing. The de level input offsets the triangle waveform over the input range of the ADC. ..
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This is the simplest of any programmable oscil lator circuit, since only one stable timing capacitor is required. The output square wave is about 25 V pk-pk, and bas rise and fall times of about 0.5 p,s. ..
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This generator will supply sine, triangular, and square waves from 2Hz to 20kHz. This complete test instrument can be plugged into a standard 110 Vac line for power. VoVT will be up to ±25 V (50 V pk-pk across loads as small as 10 0 (about 2.5 A maximum....
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This function generator, with an adjustment range in excess of 1,000,000 to 1, uses a CA3160 BiMOS op amp as a voltage follower, a CA3080 OTA as a high-speed comparator, and a CA3080 as a programmable- current source. Three variable capacitors, C1, C2, and....
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This function generator uses a CA3260 BiMOS op amp to petform both the integrator and switching functions. A 620-pF capacitor and 2-KO resistor shape feedback square wave to reduce spikes. Full audio spectrum, 10Hz to 20kHz, is covered with a single 100....
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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 swept-frequency oscillator offers an inexpensive source of discrete frequencies for use in testing digital circuits. In this configuration, the circuit generates an 80-second seguence of eight frequencies, dwelling for 10 seconds on each frequency. You....
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In a basic astable timer, configuration timing periods 11 and 12 are not controlled independently. The lack of control makes it difficult to maintain a constant period, T, if either 11 or 12 is varied. In this circuit, charge RAB and discharge R8 c....
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A positive transient, such as the power switch closing, charges r through L to a voltage above the supply voltage, if Q is sufficient. When the current reverses, the diode blocks and triggers the SCS. As the capacitor discharges, the anode gate....
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Two inverters, one resistor, and one capacitor are all that is required to make a HC(T)-based oscillator that gives reliable operation up to about 10 MHz. The use of two HC inverters produces a fairly symmetrical rectangular output signal. In the same....
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When frequency stability is not of prime importance, a simple, yet reliable, digital clock oscillator can be made with the aid of relatively few components. High-speed CMOS (HCU/HCf) inverters or gates with an inverter function are eminently suitable to....
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This simple rc oscillator uses a medium-speed comparator with hysteresis and feedback through Rl and Cl as timing elements. The frequency of oscillation is, at least theoretically, independent from the power supply voltage. ..
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An exclusive-OR gate, IClD, turns a simple CMOS oscillator into an FSK generator. When the data input increases, IClD inverts, and negative feedback through R2 lowers the circuit"s output frequency. A low input results in positive feedback and a higher....
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The common clock oscillator in Fig. 68-19A has two small problems: It might not, in fact, oscillate if the transition regions of its two gates differ. If it does oscillate, it might sometimes oscillate at a slightly lower frequency than its equation....
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Capacitor C 1 charges through resistor Rl, and when the gate level established by potentiometer R2 is high enough, the SCR is triggered. Current flows through the SCR and earphones, discharging Cl. The anode voltage and current drop to a low level, so....
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In this TMOS pulser, a negative-going pulse is applied to Ul, a high-speed CMOS buffer, which directly drives the gate ofQl, an MTP3N35. If only a 100-V pulse is required, the MTA6Nl0 can be used. ..
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Using a precision oscillator and a few CMOS counters, you can build a precise, very low dutycycle pulse generator. You can add as many counters as you desire to make the period as long as you wish. ..
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Comprising two low-power, CMOS chips, thepulse generator produces a precise pulse width in the 50 to 500 ns range. ICl is a dual monostable multivibrator (one shot) in which each positive trigger pulse initiates simultaneous positive output pulses at pins....
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The ramp generator, an inexpensive alternative to commercial function generators, provides a more linear and repeatable output than conventional analog integrators. The circuit provides a triangle waveform in burst mode; in this case, two cycles of 10.24....
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This unit is a single oscillator built around an LF351 JFET-input op amp. Resistors Rl and R2 bias the noninverting input while R3 biases the inverting input from the output. This layout provides lOO% negative feedback, but the decoupling caused by C2....
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The oscillator output of the XR-567 can be amplified using the output amplifier and high-current logic output available at pin 8. In this manner, the circuit can switch 100-mA load currents without sacrificing oscillator stability. ..
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The uA2240 timer/counter, combined with aprecision resistor ladder network and an op amp, form the staircase generator. In the astable mode, once a trigger pulse is applied, the uA2240 operates continuously until it receives a reset pulse. The trigger....
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This circuit is a high-input impedance version of the so-called diode pump or staircase generator. Note that charge transfer takes place at the negative-going edge of the input signal. The most common application for staircase generators is in low-cost....
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Simple function generators normally provide sinusoidal, rectangular, and triangular waveforms, but seldom a sawtooth. Th..
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Many function generators are based on a rectangular waveform generator that consists of a Schmitt..
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Using an EXAR XR2206, this generator will produce sine, square, and triangular waves from 10 Hz to 100 kHz. Ul is ..
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Using an Intersil ICL8038, this function generator generates frequencies from 1 Hz to over 80 kHz. Rl is the fine freque..
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This circuit uses a comparator as a Schmitt trigger (311H) and two active bandpass filters (LM318H). 3-kHz output ..
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This VFO circuit covers from 2.13 to 2.58 MHz and is intended for use with an external mixer to heterodyne the signal to desired..
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By connecting this circuit to a logic device that"s under power, you can get an indication as to its status. If the circuit is ..
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Seven-V narrow pulses from 2 Hz to 50 kHz are produced by this circuit. CI through C4 provide frequency ranges i..
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A simple pulse stretcher built with two sections of an op amp uses voltage follower U1A to drive Dl and C2. ..
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This simple and symmetrical free-running generator has a 50- output impedance, a pulse width of 100 ns..
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This straightforward circuit uses an NE555 timer as an oscillator, a 7493 counter chain and a DAC0806 D/A conver..
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This circuit adds 120 degrees of phase shift to a 50- or 60-Hz input, regardless of the frequency and amplitude fluctuations ..
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Adding a simple clamping circuit to a Harris 2620 high-speed op amp produces a glitch-free amplifier/ clipper. The op a..
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This circuit takes audio from a receiver that might have a weak CW or tone signal and uses a PLL (Ul) to recover the wea..
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This circuit can extract harmonics from various waveforms. With a sloped input waveform, the comparator produces a pulse..
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Using two CA3450 op amps and a CA3227 transistor array, this circuit will accurately full-wave rectify sign..
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This circuit combines the characteristics of an asynchronous S/R flip-flop and an edge-triggered JK flip-flop. It changes sta..
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A quad op amp makes up the heart of this function generator. Ul-a generates a square wave, and outputs this to J8. J1 and J2 are pulse outputs obtained by differentiating the square wave. Integrator Ul-b generates a triangle-wave shaper to obtain a sine wave...
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This is a simple triangle-wave generator using two IC devices and a transistor. The triangle wave is used as feedback to the square-wave generator. SI allows range switching in three ranges from 100 Hz to 100 kHz...
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By using a circuit built with a single analog multiplier and five precision resistors, an output voltage (Ko) can be made to create a second- order polynomial. The circuit implements the quadratic shown. The input terminals of IC1 are connected to create a....
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A timer (LM555CN) and decode counter is used to generate duty cycles from 10% to 100% to control the time a heating system can operate. V2 is a decode counter that can be switched from 10% to 100% duty cycle. V3A and form a latch that drive Al, LED1, and....
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This pulse generator can supplement a standalone pulse generator. Using a transistor and a 555 timer, pulse widths of 5 to 500 can be produced. The value of C3 is approximately found from the formula: C3 uF = 1.1 x10-5 T where T is the shortest pulse....
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This approach uses a Hip-Hop, a shift register, and two gates (A). Before the one-shot pulse, the output of the NOR gate is 0. Consequently, the data input of the D-type flip-flop is equivalent to the trigger. When a trigger pulse is present, the flip-flop....
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The microprocessor-controlled oscillator has a 8159 to 1 frequency range covering 2 Hz to 20 kHz. An exponential, current output IC DAC functioning as a programmable current source alternately charges and discharges a capacitor between precisely-controlled....
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Channell is wired as a conventional integrator, and channel2 as a voltage follower. When channel2 is switched on, the output will follow VJN and C will discharge to maintain 0 V across it. When channel! is then switched on, the output will initially be at....
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Built around a 555 timer IC, this pulse generator can be built into a probe for logic..
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In order to display polar quantities (magnitude and direction of a received radio signal), a sine and cosine voltage proportional to an angle (antenna direction) is needed. In this case, a sine-cosine potentiometer coupled to a directional antenna and a....
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Use of a differential capacitor allows temperature compensation of LC circuit using an NFO and N1500 ceramic. C6 is a differential capacitor that has two stators and one common rotor. When one capacitance (stator) is maximum, the other is minimum...
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Using only one IC and six passive components, this pulse generator has a frequency range of 400 to 4000 Hz and an adjustable duty cycle of 1 to 99%. A threshold detector (ICA) and an integrator (ICB) generate a triangular waveform. A positive voltage at the....
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This small device, intended primarily for modellers, allows an instant reading of the time I of a pulse in ms. It can, for example, measure the position of the servomotors, about 1 to about 2 ms, or make repetitive or non-pulsed measurements, such as closing....
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The figure shows the use of a CD4016 analog multiplex to multiplex the digital outputs back to the FUNCTION input. Since the CD4016 is a digitally controlled analog transmission gate, no level shifting of the digit output is required. The CD4051's or....
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The ratio of capacitors Cl and C2 determines division. With a positive pulse applied to the base of Ql, assume that Cl = C2 and that Cl and C2 are discharged. When {31 turns off, both Cl and C2 charge to 10 volts each through R3. On the next pulse to the....
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This is a minimum component complete Universal Counter. It can use input frequencies up to 10 MHz at INPUT A and 2 MHz at INPUT B..
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The meter will indicate the frequency from a power generator. Incoming sine waves are converted to square waves by the 100K resistor and the 6,8 V zener. The square wave is differentiated by the capacitor and the current is averaged by the diodes. The....
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In this configuration, the display reads hertz directly. With pin 11 of the ICM7027 A connected to V00, the gating time will be 0.1 second; this will display tens of hertz as the least significant digit. ..
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The circuit converts frequency to voltage by taking the average de value of the pulses from the 7 4121 monostable multivibrator. The one shot is triggered by the positive-going ac signal at the input of the 529 comparator. The amplifier acts as a de....
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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 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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The circuit consists of an ICM7208 seven-decade counter (Ul), an ICM7207A oscillator controller (U2), and a CA3130 biFET op amp (U3). Integrated circuit Ul counts input signals, decodes them to 7-segment format, and outputs signals that are used to drive a....
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This system uses an MM5369 IC to derive a 60-Hz signal from a TV burst crystal (3579 MHz). F8 and V9 producc a 10-Hz and 1-Hz signal from this 60-Hz signal...
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This meter differs from the norm in that it does not use a D`Arsonval movement or digital display to give a reading of the input frequency. Instead, the measured frequency is read from a hand-cali-brated dial. Any audio signal applied to the circuit is....
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This circuit uses the low power ICM7555 (CMOS 555) to generate the gating, STORE and RESET signals. To provide the gating signal, the timer is configured as an astable multivibrator. The system is calibrated by using a 5 M potentiometer for Ra as a coarse....
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This counter makes direct readout of frequency-generating equipment very easy when a 1-H..
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This circuit is meant to be driven by a 1-MHz standard signal of a few volts amplitude. Ul through U5 are 7490 decade counter/divider and produce a division ratio of 100,000:1. Successive divisions of 10 can be tapped off, if desired, between stages. ..
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Brief full-power flashes are obtained when the SCR conducts during positive half cycles of the line voltage. The SCR fires when the voltage at the divider, R3 and R4, reaches the gate-firing level.
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CR1, CR2, CR3, and CR4 form a bridge circuit with the SCR across the dc legs. With light on the photoconductor PCI, CI charges through Rl to about 150 Vdc. The resistance of PCI is low when illuminated, so very little voltage appears across it or C2. At....
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A 555 timer, IC1, drives a 4017 CMOS decade counter. Each of the 4017's first four outputs drives a CA3079 zero-voltage switch. Pin 9 of the CA3079 is used to inhibit output from pin 4, thereby disabling the string of pulses that IC normally delivers. Those....
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Electrolytic capacitors are unnecessary to generate a 1 cps frequency. As an scs triggers on, the 0.2 µ¥ commutating capacitor turns off the other one and charges its gate capacitor to a negative potential. The gate capacitor charges towards 24 volts....
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The driver in the package is connected as a Schmitt trigger oscillator (A) where R1 and R2 are used to generate hysteresis. R3 and C are the inverting feedback timing elements and R4 is the pull-down load for the first driver. Because of its current....
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Transistors Ql and Q2 are connected as a free running multivibrator. The output, at the emitter of Q2, drives the base of the common emitter amplifier Q3, which controls the lamp. This circuit configuration permits the flash duration, the interval between....
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This circuit uses a ring counter made up of Q3, Q4 and Q5. Q2 acts as an oscillator which triggers the SCRs Q3, Q4 and Q5 in sequence. When an SCR fires, a 0.2µ¥ capacitor provides commutation, shutting off the previous stage...
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The circuit will regulate the rms output voltage across the load (a projection lamp) to 100 volts ±2% for an input voltage between 105 and 250 volts ac. This is accomplished by indirectly sensing the light output of lamp LI and applying this feedback signal....
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This circuit is capable of driving filament lamps of nominal rating 200 mA at 60 V dc from a CMOS logic signal. The lamp or load is connected in series with the Darlington transistor TR1 and emitter resistor R5. The Zener diode ZD1 establishes a soft....
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Notes: LM3909, Capacitor, and LED are Installed in a White Translucent Cap on the Flashlight"s Back End. Only One Contact Strip (in Addition to the Case Connection) is Needed for Flasher Power..
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Inverters ICl-a and ICl-b form a multivibrator and ICl-c is a buffer. Inverter ICl-d is connected so that its output is opposite that of ICl-c; when pin 6 is high, then pin 8 is low and vice versa. Because pins 6 and 8 are constantly changing state, first....
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Applying voltage to the circuit triggers SCR1. With SCRl on, the voltage on the anode of SCR2 rises until SCR2 triggers to commu-tate SCRl. The voltage on the gate of SCRl will swing negative at this time, and only after a positive potential of 0 volt is....
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The circuit uses the primary current of a small 6 volt filament transformer to actuate a triac and energize the load. When switch Si, in the six-volt secondary, of the transformer is open, a small "magnetizing" current flows through the primary winding. This....
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Two simple arrangementsfor resistive loads are shown in A & B. The circuit in A will provide load power when the actuating contact is closed, and no power when the contact is open. B provides the reverse of this action-power being supplied to the load when....
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This lighting-control unit will fade out one lamp while simultaneously increasing the light output of another. The two loads track each other accurately without adjustments. The gate of SCRl, a silicon-controlied rectifier, is driven from a standard....
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When setting up photographic floodlamps, it is sometimes desirable to operate the lamps at lower power levels until actually ready to take the photograph. The circuit allows the lamps to operate on half cycle power when the switch is open, and full power,....
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This circuit enables a single SCR to provide fullwave control of resistive loads. Resistor R3 should be chosen so that when potentiometer R2 is at its minimum setting, the current in the load is at the required minimum level..
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The system is designed to regulate an 860 watt lamp load from half to full power. This is achieved by the controlled-half-plus-fixed-half-wave phase control method. Half power applied to an incandescent lamp results in 30% of the full light output..