This symmetric 30 mA x 15 V power supply was found in the Ferranti transistor manual from 1974. Transistors are common types at the time.
This circuit with Triac causes an ordinary incandescent lamp to flash rapidly at a frequency set...
This circuit was found in a 1967 Ferranti manual and can be applied to modern operating...
This circuit is from a 1989 Electronics Handbook. The zener diodes are 9 V x 1 W and the...