Found in a 1980s American documentation, this circuit uses programmable unijunction transistors of the time. The time interval obtained depends on the capacitors that can be changed.
This circuit appears in other articles and suggestions for circuits in this section from other...
In the figure we have the way of obtaining 220 V from two equal 110 V transformers or 230 V from...
We found this simple continuity tester in a 1995 documentation. It uses two LEDs to indicate...