Intermittent buzzer (CB20494E)

This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The transistor is a general-purpose type.

Differential Multiplexer (CB5352E)
This circuit was found in an ancient American documentation. The integrated circuit is of the time...
Digital Multimeter (CB4477E)
The basic integrated circuits of this 1988 multimeter are no longer very common today, but if...
Windshield wiper timer (CB6052E)
This windshield wiper timer was obtained in an 80's Hands On. The transistor can be the BC548 and...