This oscillator uses standard inverters, one resistor and one capacitor, and has no minimum operating frequency. R and C must be chosen such that currents into the gates are below recommended operating limits and that leakage current into the gates and into....

The HA-4900 series comparators can be used as versatile logic interface devices, as shown in these circuits. Negati..

Using one current source for tbe charge and discharge path in this circuit ensures identical rise and fall times at the capacitor terminal. A Darlington pair ensures identical biasing of the IC during the charge and discharge cycles. The period of the....

This compact LC oscillator offers a frequency range of about 1 kHz to almost 9 MHz and a low-distortion sine-wave ou..

The ·circuit includes a peak detector that irrunediately drives the readout to any new higher signal level and slowly lowers it after the signal drops to zero. The readout is a moving dot or expanding bar display. The circuit can be expanded for a longer....

Transistors Ql, Q2, and Q3 monitor the two outputs of the stereo amplifier. If the offsets exceed 2 V, Q7 is turned off, which turns off Q8 and the normally on relay. Diodes D2 and D5, together with Q4, provide a mains voltage monitor. As soon as the ac....

A bar column of LEDs is arranged so that as the audio signal level increases, more LEDs in the column light up. The LEDs are arranged vertically in 6 dB steps. A fast response time and a one second decay time give an accurate response to transients and a low....

The values of Rl, R2, and D1 are selected for the voltage applied. Using a 12-volt battery, Rl = 10 K, R2 = 5 K and D1 is a 5-volt zener diode, or a string of forward-biased silicon rectifiers equaling about 5 volts. Transistor Ql is a general-purpose UJT....

This supply generates an initial high voltage for ignition purposes. After ignition, the supply generates about 1300 to 1500 V. If a higher ignition voltage (than the 6000 V supplied) is necessary,..

The special feature of the circuit shown below is the low consumption. With voltage n 9 at the entrance and no exit load, absorbs current 50 ma, which is certainly very small compared with a quiescent current 78L05. The components that comprise it are....

This circuit modulates the current through a lamp filament. Use a low-voltage lamp with a thin, straight filament. They h..

The light sequencer uses two ICs and 10 SCRs to create.an ac sequencer. The first 10, a 555 timer, is used to provide clock pulses for 102. The 10 is configured as an astable multivibrator, and its output is on pin 3. Capacitors CI and 04, along with....

Three individual flashing circuits that use an LM3909 LED flasher/oscillator IC create the appearance of a pseudo-random firing order. The combination of CX!RV C.JRb, and C^R control the blink rate, which is between 0.3 and 0.8 s, and the inherent wide....

This circuit detects brief shorts or opens. When S2 is in the up position, the circuit indicates if there is or..

This buffer amplifier"s overall harmonic dis tortion is a low 0.01 % or less at 3-V rms output into a 500-fl load with no overall feedback. The LT1010CT offers a 100 V/p.s slew rate, a 20 MHz video bandwidth, and 100 mA of output. A pair of JFETs, ]1....

Large LCD devices of 1 or more exhibit a large driving capacitance to the driver circuits. To solve this problem, the drive circuit shown (see the figure) introduces a buffer amplifier for each of the three common lines. Each amplifier can be programmed....

A simple battery-powered switching regulator provides 5 V outfrom a 9-V source with 80% efficiency and 50 mA output capability. When Q1 is on, its collector voltage rises, forcing current through the inductor. The output voltage rises, causing A1"s output....

Ql and Q2 constitute a simple, high-speed FET input buffer.·Ql functions as a source follower, with the Q2 current-source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is....

Detection of line-current flow and indicating the flow to an electrically remote point is required in line status monitoring at a variety of points in theJelephone system and auxiliary systems. The line should be minimally unbalanced or loaded by the....

The crystal oscillator, which uses two sections of IC1, a 4001 quad 2-input NOR gate, is a standard and reliable design. The oscillator"s 1.85-MHz, square-wave output feeds IC2, a 4017 divide-by-10 counter. The count enable and reset terminals, pins 13 and....

A laptop computer supply that has 9-V output, crowbar overvoltage protection, and operates i`rom a 12-V supply is shown above. The supply voltage should be at least 3.6 V above the expected output voltage. Ql should be heatsinked appropriately. R5 should....

Transistor Ql and resistors Rl, R2, and R3 form a constant current source and the charge current might be adjusted..

This is a simple low-level noise maker that`s ideally suited to certain alarm applications. When the sounder is located in another part of the building, the sound level is loud enough to be heard, but is not loud enough to warn off an intruder. A single....

The circuit"s threshold is set by resistor R2. When the intensity of the light falling on the LDR is lowered, resistance of ..

On those occasions when we want to see if an amp works, the best tool we can use is a source of acoustic signal with a frequency around the 1 kHz. These characteristics can be merely 'tolerated', because in cases of rapid tests rarely consider whether the....

This antenna tuner is suitable for use with low-power (less than 5 W) transmitters or SW receivers. S2 selects inductance and S2 connects the 365-pF capacitor to either the transmitter or the side of the inductor. The tiny tuner is comprised of a tapped....

This circuit"s frequency of oscillation increases directly with light intensity. The greater the light intensity, the higher the frequency of the oscillator. The 555 timer operates in the astable oscillator mode where frequency and duty cycle are....

This circuit is useful where fast signal acquisition and high precision are required, as in electronic scales. The filter's time constant is set by the 2 ohm resistor and the 1 µ capacitor until comparator No. 1 switches. The time constant is then set by....

This light-wave receiver consists of a 741 operated as a preamplifier and an LM386 operated as a power amplifier. Potentiometer R2 is the gain control. Various kinds of detectors can be used as the front end of the receiver. Phototransistors are very....

A relay and two diodes are all tliat is needed the relay performs the job of a buzzer so no annunciator is required. When the lights are left on, but the ignition is off, the normally closcd relay contacts are in series with the relay coil. That means the....

Circuit (a) lets you delay the leading edge of a positive pulse while leaving the trailing edge almost unaffected. A positive input transition, inverted hy IC2, has no effect on IC1B. However, when the positive transition reaches IC1A, (delayed hy the....

A normally open pushbutton switch (SI) delivers a positive input pulse to pin 4 of Ul, triggering the 1C into action. The output of Ul at pin 6 supplies base-drive current to a Darlington pair comprised of Q1 and Q2, activating . 10- capacitor and any....