In a September 1992 Radio Electronics article, we found this basic 555 circuit used to generate fixed times. Capacitor C1 and resistor R1 determine the time. The circuit drives an LED.
This general-purpose two-transistor circuit was found in the November 1993 issue of Electronics Now. The...
This circuit with integrated TTL 7400 has a good teaching purpose, drawing one of two LEDs. The...
This circuit is from 2002 documentation, requiring a symmetrical source of 6 to 12 V. The signal...