This interface shield circuit is from the 1983 Intersil Databook. The components used are uncommon today. ADCs are low-cost digital converters. The power source voltage must be 5 V.
This is the version of the previous circuit with shadow activation. The circuit can use relays from...
This 90's project shows how to use an old cassette recorder to practice telegraphy. In position A of the...
Using the 741 this basic circuit was found in the November 1973 Radio Electronics magazine. The...