This circuit was found in 80's Popular Electronics. The components used are common and the number of indication channels (LEDs) can be changed.
Only one LED is turned on when S1 and S2 are pressed. The LED that will be on is just the...
This circuit is based on one of the first germanium transistors. The power comes from a solar cell...
This circuit was found in an American 80's circuit board. The components used are current except the...