12 LED VU Meter Circuit

12 LED VU Meter Circuit diagram

Here the 12 LED VU meter circuit. This is a simple visual indication of the audio level signals, adaptive to various user needs. Can be adapted to different input levels, adjustable by trimmer TR1 (state) - TR2 (Gain), then rectified by diodes D1-D2 (standard negative mark-recovery periods) and driven in the main circuit indication, consisting of the diodes D3 up to D13, transistors Q2-Q13 and materials that exist around them.

The visual indicator is taken from the series of diodes LED LD1-13. Each Led illuminates when the level changed during about 0,65 V. The power requirements are 100 ma full term. We can add as many steps we want LED, always assuming the power where you need the new LED.

Components List
R1 = 47Kohm
R2,3 = 1Mohm
R4,R7 = 1Kohm
R5 = 100ohm
R6 = 18Kohm
R9,11,13,15,17 = 560ohm
R19,21,23,25,27 = 560ohm
R29,31 = 560ohm
R8,10,12,14 = 4.7Kohm
R16,18,20,22 = 4.7Kohm
R24,26,28,30 = 4.7Kohm
C1 = 10uF/25V
C2 = 100nF/100V MKT
C3 = 4.7uF/25V
C4 = 4.7uF/25V
C5 = 10uF/25V
C6 = 47uF/25V
C7-8 = 100nF/100V
TR1 = 100Kohm Trimmer
TR2 = 4.7Kohm Trimmer
LD1 until LD7 = LED Green
LD8,LD9,LD10 = LED Yellow
LD11,LD12,LD13 = LED Red
D1 until D13 = 1N4148
Q1 until Q13 = BC550C - BC549B
IC1 = TL071
IC2 = 7812 [With Heatsink]
All Resistors is 1/4W 1 -5%

12 LED VU Meter Circuit source page: users.otenet.gr