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.
In fact, it is a RF field indicator with an operational amplifier equivalent to the 741. This...
The critical components of this project from a 1978 publication are the transformers, which can be...
This 1.5 A source for FM transmitters was originally intended for the transmitter described in...