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.
Obtained from a 1996 documentation, this circuit uses common components and has a voltage gain of 200...
This precision circuit can provide timings from 0.2 milliseconds to 3 minutes accurately. The...
Found in RCA documentation from the 90s, this bass and treble control uses an operational...