We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors with another 4011. The power can be made with voltages from 6 to 12 V.
This circuit was found in an American documentation from the 80's. The transistor is a...
This transistorized circuit, with germanium transistors from the 60s, was obtained in a technical...
In the figure we have the way to use a voltage comparator powered by a voltage to control a...