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 for 1 kHz sinusoidal signals uses a common operational amplifier circuit and is...
This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The...
This is an amplifier stage with a typical germanium transistor from the 60's to the 70's. The...