We found this circuit in the July 1990 issue of Radio Electronics magazine. The frequencies are given by capacitors C2 and C3, which can be changed.
We found this 4W transmitter in a Mullard transistor manual from 1960. The circuit is powered by...
The response curve of this circuit has a maximum boost of around 6 kHz. The vertical scale is in...
Using the 555 this circuit was found in a Popular Electronics from the 90's. The circuit directly...