This interesting digital counter with relays with complementary outputs was found in the Radio Electronics magazine of October 1961. The supply voltage is in accordance with the relays used.
This drain dip oscillator was found in an old English documentation. The JFET can be of any type...
This circuit was found in a 1977 timer cookbook. The circuit can generate signals with up to 99%...
This didactic circuit was found in an English publication of 1965. The sensor is an LDR and...