Introduction: LED Bar Graph

Picture of LED Bar Graph

this led bar graph contains only three LED s and each LED show the low, mid range and high frequencies according to the audio played, this bargraph can be used in audio amplifiers, the circuit is for a 40w amplifier,  connect the circuit in parallel to the speakers and no external power supply is needed........

Step 1: Parts List

Picture of Parts List

1 x red LED ( or any color you like)
1 x Blue LED (or any color you like)
1 x Green LED (or any color you like)
1 x 1uf capacitor (electrolytic) 16v
1 x 3.3uf capacitor 16v
1 x 4.7uf capacitor 25v 

Step 2: Circuit Diagram

Picture of Circuit Diagram

make the circuit according to the circuit diagram

Step 3: Conclusion

Picture of Conclusion

hope you like the circuit... And please rate it


usbg3rd (author)2012-01-25

what is the working principle of the circuit? correct me if i m wrong.
when high frequency comes then the capacitor gets short (theoretically) then all LED's should glow simultaneously. and in case of low frequency no led should glow

also what is the voltage rating of the capacitors?

sooraj619 (author)usbg3rd2012-02-09

since the values of the capacitors are different all leds will not glow simultaneously

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