This circuit of starting lights for auto-race was found in an English documentation from the 80's. The LEDs must be of different colors, for greater realism.
This circuit warns you with an audible signal every time someone passes through a door and forgets to...
We found this circuit in an old English documentation from 1979. The circuit is very sensitive, because...
This low power amplifier was found in a Japanese publication from the 1960s, using transistors from that...