Found in an Australian documentation from 1991, this circuit was sold in a kit at the time. It is a small FM transmitter with a very common configuration, also found in other projects on this site.
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
Found in 1965 General Electric technical documentation, this half-wave circuit controls shunt type...
The power supply shown in the figure provides voltages between 0 and approximately 15 volts, with...