This relay shield circuit for old computers was found in January 1983 Radio Electronics magazine. The relays are sensitive types with currents up to 200 mA.
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single-step motor...
We found this circuit in a 1980s publication on telephony. The circuit uses an integrated...
This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The...