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Sound Level Meter

This nifty sound level meter is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out. The whole circuit is based on the LM3915 audio level IC and uses only a few external components. This circuit can also be integrated into audio amp projects.


Schematic for sound level meter


Total Qty.
C112.2uF 25V Electrolytic Capacitor
R111K 1/4W Resistor
D111N4002 Silicon Diode
LED1-LED1010Standard LED or LED Array
U11LM3915 Audio Level IC
MISC1Board, Wire, Socket For U1


1. V+ can be anywhere from 3V to 20V.

2. The input is designed for standard audio line voltage (1V P-P) and has a maximum input voltage of 1.3V.

3. Pin 9 can be disconnected from ground to make the circuit use a moving dot display instead of a bar graph display.

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