Thermocouple Amplifier circuit (CA3193)

Battery Test Circuit Circuit

Using this circuit, tiiree levels of voltage can be displayednormal (11 to 15 V), liigh (>15 V), and low (11 V). When the voltage is low, the LED glows steadily. In the normal range, the LED is off. When the voltage is high, the LED blinks at a 1-Hz rate.

Video modulator 2

This circuit permits direct connection of composite video signals from video games and microcomputers to the antenna terminals of TV sets.

Wideband radiation monitor

A sensitive radiation monitor may be simply constructed with a large-area photodiode and a quad operational amplifier. Replacing the glass window of the diode with Mylar foil will shield it from light and infrared energy, enabling it to respond to such nuclear radiation as alpha and beta...

Electronic Music Maker

This electronic music maker uses an astable oscillator circuit that is controlled by a photocell. The light falling

Inexpensive Isolation Transformer (Impromptu Setup) Circuit

Using two 12-V filament or power transformers, an impromptu isolation transformer can be made for low-power (under 50 W) use in testing or servicing. SOI is an ordinary, duplex ac recept-able.

Musical chime generator

The circuit is that of a multiple feedback bandpass filter. A short click (pulse), makes it ring with a frequency which is its natural resonance frequency. Oscillations die away exponentially and closely resemble many naturally occuring percussive or plucked sounds. The higher the Q the longer...

Active inductor

An active inductor is realized with an eight-lead IC, two carbon resistors, and a small capacitor

Wien Bridge Sine Wave Oscillator Circuit

This Wien-bridge sine-wave oscillator uses a 2N3819 as an amplitude stabilizer.