Alarm Siren 4001 (CB24391B)

This monotone alarm oscillator circuit was found in July 1975 Radio Electronics magazine. Power is supplied by the output transistor.

| Clique na imagem para ampliar |

Filter selection circuit with PIN diode (CB20933E)
Found in Popular Electronics from the 1980s, this circuit is intended for switching filters with...
3 W Megaphone (CB18418E)
This circuit was found in a Japanese publication from the 1960s. The circuit uses a class B stage...
Multitone Doorbell (CB19512E)
This circuit appears in other versions in this same section of the website and in other sections with...