This windshield wiper timer was obtained in an 80's Hands On. The transistor can be the BC548 and the relay is 12 V sensitive. The time is set to R3.
This circuit was found in a 1992 publication. What it does is to light an external lamp when it...
Found in a book on transistors from 1954, this circuit can modernly be used as a relay shield. A 1k...
This Schmitt trigger was found in a 1969 Ferranti documentation. Transistors may be modern...