The transistor in this project found in the July 1994 issue of Electronics Now magazine can be any general-purpose type. The circuit is powered by the relay voltage up to 12 V.
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...