Strobe LED display circuit (1)

When fast enough to eliminate flicker (approximately 10% duty cycle), continuous gating of a single LED display can reduce the power requirements on the LEDs and eliminate the need for power dissipating resistors in series with the digital fields. The 7492 binary counter used in the circuit is divided into 10, which are continuously clocked by the 1000Hz signal of the external counter time base. Each of these 10 counters is decoded by a 7442 decoder and used to turn on a PNP type switching transistor in series with the anode of each 7-segment LED digital display .