We found this circuit in the December 1968 issue of Radio Electronics magazine. The circuit is used with high-impedance magnetic headphones. The transistors are from that time.
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...
The circuit shown is from National Semiconductor's Linear Applications Handbook. The LM3900 is a...
This circuit was found in a 1976 documentation. It can be used with old tape recording mechanisms for...