DS

The circuit below uses two quad voltage comparators (LM339) to illuminate a series of 8 LEDs indicating volume level. Each of the 8 comparators is biased at increasing voltages set by the voltage divider so that the lower right LED comes on first when the input is about 400 millivolts or about 22 milliwatts peak in an 8 ohm system. Circuit diagram : 8 Stage LED VU Meter Circuit Diagram The divider voltages are set so that each LED represents about twice the power level as the one before so the scale extends from 22 milliwatts to about 2.5 watts when all LEDs are lit. The sensitivity can be decreased with the input control to read higher levels. I have not built or tested this circuit, so please let me know if you have problems getting it working. The power levels should be as follows: 1 LED = 22mW 2 LEDs = 42mW 3 LEDs = 90mW 4 LEDs = 175mW 5 LEDs = 320mW 6 LEDs = 650mW 7 LEDs = 1.2 Watts 8 LEDs = 2.5 watts

Here are very simple project of Sound VU Meter Circuit Diagram. This circuit is a sound level meter, very simple, but very effective for your sound system or test bench. This type of circuit is also called a VU meter. 'Abbreviation means "unit volume" is used to express that the average value of a music signal over a short period of time. Sound VU Meter Circuit Diagram The VU meter described here is what is called a type "passive". This means that does not require a separate power source, since the power is supplied by an input signal. This makes it easier to use:. Just connect it to the speaker terminals (polarity does not matter) and is ready to use.

Here is a simple Electronic Circuit Project of VU Meter 1 with transistor Circuit. This is Simple Circuit of optical index of level of sound signals, adapted in various needs of user. It can be adapted in various levels of entry, regulated from trimmer TR1 (Level) - TR2 (Gain), then it is rectified by the D1-2 (cutting off of negative periods of signal-rectification) and drived to the main circuit of index, that it is constituted by D3...D13 , the transistors Q2-Q13 and the materials that exist around them.  VU Meter 1 Using with Transistor Circuit Diagram: The optical index him we take from the line of LED LD1-13. The each led turns on when the level is altered at 0,65V roughly. The requirements in current are 100 ma with complete index. We can add all units LED we want, always calculating the current where they will need the news LED. Parts List of  VU Meter 1 Using with Transistor :