We found this circuit in the October 1980 issue of Radio Electronics magazine. The circuit uses general-purpose transistors driving a relay.
Found elsewhere in this section, this circuit mimics the noise of a steam locomotive. This was...
This circuit was obtained in an American documentation from the 80's. The transistors can be...
This circuit is from a 60's documentation. The capacitance C1 can be between 20 pF and 0.01 uF...