This circuit was found in a 1967 Japanese documentation. It consists of a touch control system with two transistors from the time. The circuit uses a power source and sensitive relays.
September 2017 - Microchip's MCP6411 operational amplifiers for frequencies up to 1 MHz are in...
We found this circuit in a 70s publication. Transistors are general-purpose types of the time. The...
This receiver circuit was found in a Hands On Electronics from the 90s. The circuit uses a PLL...