Sound Level Meter

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easy
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Features
Schematic
Parts List
Connections
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This nifty sound level meter is a perfect one-chip replacement for the standard analog meters. It is a 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.

Parts

C1	2.2uF 25V Electrolytic Capacitor
R1	1K 1/4W Resistor
D1	1N4002 Silicon Diode
LED1-LED10	Standard LED or LED Array
U1	LM3915 Audio Level IC
MISC	Board, Wire, Socket For U1

Notes

V+ can be anywhere from 3V to 20V
The input is designed for standard audio line voltage (1V_P-P) and has a maximum input voltage of 1.3V
Pin 9 can be disconnected from the ground to make the circuit use a moving dot display instead of a bar graph display