This circuit activates a buzzer when the voltage applied to the input falls below a preset value in R1. The circuit is from an 80's American documentation.
This circuit for VCR recording heads was found in the February 1990 issue of Radio Electronics magazine....
This very simple continuity tester uses a small 1.5 V lamp (type used in flashlights). Can be...
This commercial radio with 3 earphone listening transistors was manufactured in Japan in the...