Applications for this circuit include hearing aid, stethoscope, etc. Transistors are general purpose and powered by a single 1.5 V battery.
This circuit was found in a Texas Instruments optoelectronics documentation. The gain depends on...
This oscillator circuit is from a Radio Electronics magazine from September 1960. The frequency depends...
Using a reed relay, this protection circuit depends only on the adjustment of the closing point by a wire...