This circuit is from American documentation from the 1980s. The circuit can make use of any common NPN transistor and the power comes from two small batteries.
This circuit is from 80s documentation, using still common CMOS components. The display is 7...
This circuit was obtained in an English magazine from 1979, but it can be easily assembled with...
Found in Electronics Now, this circuit generates signals for testing like a signal injector. The...