This 10 LED VU meter circuit has only a few parts but is useful as an indicator for the measurement of entering acoustic signals. The circuit is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out
LM3914 VU Meter Circuit
The circuit is built around an LM3914 IC. The input signal from the VU meter is put on pin 5 of IC1. Through pin 9 of IC1 is the display mode sets (bar or dot instructions). In the drawn state IC1 works in the dot mode. When pin 9 is coupled to pin 3, the IC works in bar mode. Obviously the whole circuit consumes less power in dot mode.
C1 : 2.2uF/ 25V Electrolytic Capacitor R1 : 1K Resistor D1 : 1N4002 Diode LED1-LED : 10 x LED or LED Array U1 : LM3915
- V+ can be anywhere from 3V to 20V.
- The input is designed for standard audio line voltage with has a maximum input voltage of 1.3V.
- Pin 9 can be disconnected from ground to make the circuit use a moving dot display instead of a bar graph display.