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.
This is the traditional configuration of a differentiator with an operational amplifier. This was...
This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The...
We found this circuit in Motorola's Circuit Applications for the Triac 1971 manual. The circuit is for ½...