This simple metronome, from 1985 documentation uses only transistors and has two settings. For voltages above 6 V, up to 12 V, replace the BC557 with a BD136.
This circuit allows 220 / 240V shavers to be used in the 110V network. The diodes can be general...
Found in July 1975, Radio Electronics magazine this circuit can use any operating circuit,...
Here we have in the figure the configuration of the circuit as a conventional Darlington. In this...