This circuit is from an Electronics World of 1968. The transistors are of the time and the power is supplied with a voltage of 40 V. The circuit is high fidelity.
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...