This circuit was found in an article about the 555 in the November 1992 Radio Electronics magazine. The circuit uses a 12 V relay and has two timing ranges.
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...