This circuit is from a Mallory 1968’s documentation. The integrated circuit is of the time and the transistor admits equivalents.
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
Crystals from 100 kHz to 1 MHz can be used in this 1957 Raytheon circuit. 4 can have values...
This window comparator configuration is from a 1980 publication. It is a conventional circuit that...