We found this circuit in a Radio Electronics from December 1963. The circuit combines valves and transistors and has a high input resistance. The circuit is powered by two batteries.
Found in a 90s Popular Electronics, this circuit is based on a uA739, an unusual component today....
This circuit is from a 1982 publication. It is a sequential effect of accelerated LEDs. The...
In the figure we have more circuit that makes use of transistors and that has excellent...