This circuit, which can be found elsewhere on this site, detects positive pulses of a signal. The circuit was suggested in Texas Instruments documentation from the 1980s.
This VFO circuit generates signals from 2 Hz to 50 Hz. We found it in Popular Electronics from...
Taken from the 1982 SGS manual on integrated circuits, this preamplifier was used in commercial...
This is an interesting sound effects circuit that uses only discrete components. Components are common...