Despite being found in a 1980 publication, this circuit uses components that can still be found easily. The circuit feeds an array of LEDs that run randomly, stopping at one.
In the figure we have the way to use the LM3914 as a scale of bar LEDs or moving point. The...
We found this circuit in a European publication of the 1980s. The transistor could be the BC549. The...
We found this simple continuity tester in a 1995 documentation. It uses two LEDs to indicate...