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 light comparator is of the window type already explored on this website in several...
Using the integrated circuit DCP01051D this circuit was found in the magazine Electronics Now of...
This filter with the operational 741 passes the frequency range between 300 Hz and 3,400 Hz. This...