LED flasher (CB22143E)

The transistors in this circuit can be the BC548. Capacitors determine the frequency and can be changed. The supply voltage can also be changed.

Audible warning (CB9204E)
This circuit that generates a special sound was found in a Popular Electronics from the 90s. The...
20 W BTL Amplifier TDA1003 (CB15235E)
This bridge amplifier (BTL) is from the SGS linear integrated circuit manual. The circuit is...
Micro Buzzer (CB20336E)
In the figure we have a simple way to produce tone in a piezoelectric transducer. The frequency depends...