Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to 15 V. The operational amplifier is from the era and can be replaced by modern equivalents.
This proximity relay circuit was found in the July 1990 Radio Electronics magazine. The supply...
This sensitive circuit for triggering relays was found in an old English publication. It works with...
This circuit was obtained from a 90’s Linear Technology documentation. The circuit provides...