Variable LF AC voltage generator - has oscillator producing triangular and square wave for clipping and limiting circuit to combine into sinusoidal wave

摘要

The generator has an output variable in frequency from 4 to 35Hz. The output is sinusoidal and can be varied between 0 and 4 volts. The generator is intended for use in the studies of human brain activity and in corrective treatment of some psychological problems. The oscillator consists of two integrated circuit operational amplifiers, one having a triangular output, the other a square wave output. A clipping and limiting circuit combines these into a waveform very close to sinusoidal. The sinusoidal wave is fed via an amplitude controlling potentiometer to a third amplifier feeding two cranial electrodes.