The presented circuit uses a PNP transistor, which can be the BC558. Observe the polarity of the supply. The circuit is suggested by Texas Instruments opto-electronic documentation.
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...