This well-known circuit version of the siren was obtained in a Colectro Handbook from the 70s. The transistors are of general use, with Q2 being a BD136 for greater power with power from 6 to 12 V.
Figure bellow shows how the flip-flops of a 4027 can be connected to perform a divide-by-5 counter [odd...
This circuit is interleaved with the source of a portable AM or FM radio previously tuned to a...
This control allows to start or stop a motor up to 3 or 4 A with a low intensity signal. The...