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Mini LED Chaser [Audio Based]


This mini chaser circuit displays a moving light, whose speed varies according to the audio input.
The audio input is amplified by IC1 and the output is converted to DC by the Diode D1 and the capacitor at its output. This DC is fed to pin 5 (control voltage) of IC2 whose frequency is adjusted by VR2
circuit diagram of mini chaser

The output of this oscillator is given to a counter IC which counts to ten. When the input changes, the DC level at pin 5 changes and the frequency of oscillator also changes, varying the speed at which the LEDs turn “ON” and “OFF”. The LEDs can be mounted on a bright panel and arranged in any attractive arrangement.
For extra brightness add two LEDs in series. Foe each LED, a separate resistance is not needed; a common 120 Ω resistor is enough. The supply can be between 6V and 12V. This circuit consumes only about 15mA.
Do not add LEDs in parallel at the output of the IC3 as it cannot provide the current. Change in supply voltage will slightly affect the “running” speed of the LEDs. So a stable supply must be provided if the change in speed is not much. Adjust VR1 to give better results.

PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon unless stated otherwise)
R1 = 1 MΩ
R2 = 47 KΩ
R3, R4, R6, R7 = 100 KΩ
R5 = 10 KΩ
R8 = 1 KΩ
VR1 = 100 KΩ
VR2 = 47 KΩ
Capacitors
C1 = 0.1 µF
C2 = 10 µF/25V
C3 = 1 µF/16V
Semiconductors
IC1 = µA741
IC2 = NE555
IC3 = CD4017
D1 = 1N4001
LED1 – LED10 = different color LEDs

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