This circuit was found in the February 1980 issue of Radio Electronics magazine. The digital circuit was shown in two parts, using 20 LEDs in a configuration with the LM3914.
This circuit provides a pulse train of 4 MHz or at another frequency determined by the crystal during...
The number of pulses produced by this circuit depends on the switch pressed. The circuit is from...
This circuit prevents the passage of frequencies in a range starting at 1 kHz and can be adjusted...