Found in technical documentation from National Semiconductor, this circuit provides a voltage of 3.3 V with 500 mA at the output. The component is from the period.
With this circuit it is possible to use a common hair dryer as a hand dryer. The circuit is timed...
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...
This circuit was obtained in a 1975 magazine, but it can be easily assembled using BC548...