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 1965 Philips circuit uses old company transistors like the BFY51 and BFY50. The circuit is...
This circuit is from 1991 but can be assembled with a 2N2646 unijunction transistor. When turned on,...
We found this circuit in a 1998 documentation. It tests common household appliances to see if they...