This circuit produces the sound of a motorcycle or an outboard motor. The frequency is adjusted in the pot. For supplies above 9 V the BD136 must be equipped with a small heat sink.
This circuit was found in a Popular Electronics from the 90s. The circuit uses general purpose...
Found in Raytheon's 1960s transistor circuit manual, this circuit employs the CK722, one of the...
This encoded lock circuit with alarm for use in homes was found in a publication from the 90s. The...