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 receiver for listening to the TR-23 phone was manufactured in Japan in the 1960s. The circuit is...
The two previous circuits show the INA185 a current sensing amplifier in basic applications. This...
This small digital transmitter uses a 1 MHz crystal, or another nearby frequency, to produce a...