This transistorized stage has a high gain, being adjusted by VR1. The circuit can be used as an excellent audio preamp. We found this circuit in a 1996 English publication.
This effect circuit already includes the amplifier that can be replaced by more modern types. The...
This telegraph microtransmitter for a frequency determined by the coil and the crystal was found...
This circuit was found in the November 1989 Radio Electronics magazine. Power supply depends on...