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

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 

what is the working principle of the circuit? correct me if i m wrong.<br> 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 <br><br>also what is the voltage rating of the capacitors?<br>
since the values of the capacitors are different all leds will not glow simultaneously

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Tags: LED Bar Graph
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