This windshield wiper interval switch was found in the April 1990 issue of Radio Electronics magazine. The circuit uses integrated circuits that are still readily available.
This circuit was obtained from a 1977 magazine, but can still be mounted using BC548 for TR1 and...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
The figure shows how to add a Darlington stage to an operational amplifier in order to obtain a...