This circuit was found in the February 1985 issue of Radio Electronics magazine. It is based on an AY-3-1350 melody generator that was common at the time. It is suitable for analog lines only.
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...