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.
Using transistors at the time, this circuit was found in a 1967 Ferranti documentation. The...
This circuit provides voltages and a 1 kHz signal for measurement bridges. The circuit is from...
We found this oscillator in an integrated circuit manual from the 90's. The circuit shows how to...