VU Meter Made on a Breadboard

The project is based on LM3915/LM3916 to produce a VU meter with the level indication using 10-segment LED bar graph.

The VU meter circuit was built on a breadboard with a few components used such as resistors, stereo jacks, capacitor, power supply with 3V-25V rating, and a few connecting wires. The use of capacitor is only optional and is suitable if the cable used between the LEDs and chip is more than 6 inches.

LM3916 is a monolithic integrated circuit that detects analog voltage levels and powers ten LEDs, LCDs or vacuum fluorescent displays, supplying an electronic version of the popular VU meter which can be calibrated by decibel values and used as bar graph/LED driver chip. It switches the negative voltage and not the positive. This is the reason why the LEDs are attached to the positive in the breadboard. For LEDs to light up in order, pin 1 should go to the first pin on the LED followed by pins 18-10.

To be able to listen to music, two stereo jacks are wired together where 3 wires are hang off from one while the negative goes to pin 4 on both chips.

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