1 kHz low pass filter (CB7579E)

This filter can be implemented with almost any operational. The power suppply must be symmetrical.

Photo Alarm with PUT (CB1306E )
We find this circuit in a French publication of the 1980s. The circuit uses an unusual component which...
Tone Control Preamplifier (CB14625E)
The circuit shown is from the National Semiconductor FET manual. Field effect transistors and...
Siren 555 (CB10651E)
This circuit was obtained in a 1999 English magazine. We can easily assemble it with a BD136 or...