Found in a 90’s 73 magazine for radio amateurs, this circuit provides a few milliamps of output with -15 V from a 3 V input, when the consumption will be 10 mA.
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...