This circuit provides a cheap alternative to the LM3915 series LED displays. The meter relies on a square-wave oscillat..

The circuit provides a simple means of determining the succession of phases of a 3-phase 120 V source used in synchro work. Terminals A, BT and C are connected to the three terminals of the source to be checked. If the neon bulb lights, interchange any two....

Tl is tuned to converter-output frequency Ul to provide 45-to-50-dB gain, depending on the design of Tl and T2. C2, C..

This circuit gives a positive output when the input voltage exceeds 8 volts. Between these limits the output is negative. The positive limit point is determined by the ratio of Rl, R2, and the negative point by Rl, R3. The forward voltage drop across the....

This very special mains-operated dimmer for domestic or industrial lights is not available in proprietary form: it ena..

As shown, a 555 timer (Ul) is configured as an astable multivibrator (oscillator) with a 400:1 duty cyc..

Circuit for applying a dc-coupled FM or PPM to a 555 configured as an oscillator. IC-1 - Motorola MC-1374P. IC-2 - National LH0002C. L1, L2 - Mouser Electronics #421IF200. C1. C2 - Silver mica, 300 pF. All 0.1 uF cap., ceramic disc, 16V. C3 - 100 uF, 10 V,....

Using a single chip LM324 can, with active R-C networks, reduce the size of a 3-phase waveform generator, and prove useful in compact and stable 3-phase inverters. One quarter of an LM324 is used as a Wien bridge oscillator generating a pure sinusoidal....

This circuit provides a low cost and reliable method of testing zener diodes. RVl can be calibrated in volts, so that when LED 1 just lights, the voltage on pins 2 and 3 are nearly equal. Hence, the zener voltage can be read directly from the setting of RVl.....

This encoder uses a single contact per key keyboard and provides all other switching functions electronically. The diode connected between terminals 8 and 15 prevents the output from goitrg more than 1 V negative with respect to the negative supply Vss.....

Sensing short circuits in equipment that performs under water is especially critical, but Fig. 20-4"s wet-mat..

This circuit combines two LTC1043s with a based humidity transducer in a simple charge-pump based circuit. The sensor specified has a nominal 400 pF capacitance at RH = 76%, with a slope of 1.7 pF/% RH. The average voltage across this device must be zero.....

The system utilizes the H21A1 and a chopper disc to provide superior speed regulation when the dynamic characteristics of the motor system and the feedback system are matched to provide stability. The tachometer feedback system illustrated was designed....

The NPD5566 monolithic dual is used in a differential multiplex application where Rds(ON> should be closely matched) for the monolithic dual tracks at better than ±1% over wide temperature ranges (-25° C to +125° C), this makes it an unusual but ideal....

The low output impedance of a closed loop op amp gives ideal line-noise immunity, while the op amp's offset voltage drift provides a temperature sensor. Using the op amp in this way requires no external components and has the additional advantages of a....

The device remains dormat (in an off condition) until some sound causes it to tum on. The input stage is a 741 operational amplifier connected as a noninverting follower audio amplifier. Gain is approximately 100. To increase gain raise the value of R2..

Transistors Q1 and Q2 amplify the incoming signal, and the gain is such that the input will overload when used with an electric guitar. RVl adjusts the amount of feedback present, and hence voltage gain. The output is, therefore, a squared version of the....

The circuit uses an ICM7213 precision one minute/one second timebase generator using a 4.1943 MHz crystal for generating pulses counted by an ICM7217B. The thumbwheel switches allow a starting time to be entered into the counter for a preset-countdown type....

The pulse repetition rate is selected by positioning SI to the desired position and the rate remains essentially constant when the resistors which determine on-period and off-period are adjusted. ..

This combination sync stripper and universal video interface can solve a lot of problems for you, including Super-Nintcndo-to-anything interfacing, video overlay and scope TV frame locking. Kits, fully tested units, and custom cable assemblies are available....

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....

The circuit has a frequency response that ranges from 100 Hz to 3 MHz; the gain is about 30 dB. Field-effect transistor Ql is configured in the common-source self-biased mode; optional resistor R1 allows you to set the input impedance to any desired value.....

This low-cost operational-amplifier circuit (A) generates four different functions with adjustable periods. For the components shown here, the period of the output waveforms is given by T = 4RC and T = 2RC. With switch SI in position A, VI is a triangular....

The shift pulse amplitude is less than 15 volts. If a stage is off, the shift pulse will not be coupled to the next stage. If it is on, the diode will conduct triggering the next stage. Just prior to the shift pulse the anode supply is interrupted to turn....

This switching circuit acts like a bank of interlocked mechanical switches; pushing one of the buttons latches its corres..

The temperature sensor provides an input to pin 3 of the NE5037 of 32 mV/°C. This 32 mV is the value of one LSB for the NE5037. The LM334 is a three-terminal temperature sensor and provides a current of 1 p.A for each degree Kelvin. The 32-KO resistor....

An infrared LED and a phototransistor are used for each eye. Half of a 556 timer IC (ICl-a) functions as an as table multivibrator oscillating at a frequency of about 1 kHz. That IC drives transistor Ql which in turn drives the two infrared LED's, LED1 and....

This screen uses ten LEDs to display a voltage range of 10.5 to 15 volts. Each LED represents a step 0.5wvolt tension. The heart of the circuit is the 3914 points LM / bar display driver. Trimming potentiometer R5 is adjusted so that 7.5 volts is applied to....

The FM oscillator/modulator is a voltage-control led oscillator, which exhibits a nearly linear output frequency versus input voltage characteristic for a wide deviation. It provides a good FM source with a few inexpensive external parts..

When an asterisk * is pressed on the touch-tone phone, TCI a DTMF decoder, controls on-hold logic. Audio from the FM receiver IC4 is.placed on the telephone line when a hold condition is present. RY2 is a DPDT 12-V relay. To place a caller on hold,..

The circuit provides unambiguous LED + or - bar readout with steps of 0.1%. The reference frequency is multiplied by the PLLIC1 and divider IC9 to output 64 ? F (ref) and this is then gated by dividing F (measure) by 32 in IC8 thus is F (ref) = (measure)....

Q1 and Q2 form a voltage amplifier which has sufficient gain to be overdriven by a rela-tively low input, such as an electric guitar. The result is that the output from Q2 is a Squared-Off verson of the input, giving the required fuzz sound. RV1 adjusts the....