This circuit rejects frequencies around 1 kHz and can be adjusted using C1. Equivalent operational amplifiers can be used, and the power supply must be symmetrical.
This circuit is from a 1968 Electronic Design. The components are from the era and the operating...
This circuit was found in an Electronic Design from the 90s. The integrated circuit is from that...
This circuit, from a 1988 documentation, activates a relay for a period and has a touch shutdown as...