This simple 1-transistor audio preamplifier appeared in the June 1968 Radio Electronics magazine. The transistor is a general-purpose type of the time. The gain is 14 dB.
This circuit uses a common multimeter on the voltage scale. The calibration of the scale should be...
This circuit is intended to drive bistable relays and can be used as a shield for...
This circuit was found in a PE Hobbyst Handbook of 1989. It uses a black light fluorescent of the time....