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 signal follower, from a publication from the 1970s, uses old germanium transistors such as...
This sophisticated photometer that has a light comparator with LED indicator came out in an...
The presented circuit is used to test ordinary fluorescent lamps. This circuit also has a mains...