This circuit makes use of a stroboscopic tube, a component that no longer exists today. The circuit is from the 70's and can be adapted to use mains voltage.
In the figure we present a circuit that has an insulation voltage of 2,500 V at 60 Hz and...
We found this circuit in a Popular Electronics from the 80s. The circuit is based on the LM3909, a low...
This timer was found in a 1980 publication. With the BC548 for Q1, an 8-ohm speaker with 6 V power...