Found in European documentation from the 1980s, this circuit was originally designed for computer applications of the time. However, the basic idea can be adapted for use with microcontrollers.
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...