Part List :
R1 22kΩ
R2 220Ω
VR1 50kΩ Preset
C1 1µF 16V
C2 0.01µF (103)
C3 10µF 16V
D1 – D10 1N4148
D11 – D16 LED
IC1 NE 555
IC2 CD 4017
The input of the counter is called the CLOCK line (555). The 10 outputs become active, one at a time, on the rising edge of the waveform from the 555. Each output can deliver about 20mA but a LED should not be connected to the output without a current-limiting resistor (220Ω in the circuit above).
The first 6 outputs of the chip are connected directly to the 6 LEDs and these “move” across the display. The next 4 outputs move the effect in the opposite direction and the cycle repeats. The animation above shows how the effect appears on the display. Using 6 LEDs, the display can be placed in the front of a model car to give a very realistic effect.
