Sound Level Meter base on LM3915

[ryeeson]

lm3915

i'm a newbie.

i want to design Sound Level meter base on LM3915 IC but i dont know how to connect the input signal.

LM3915 bassicly is to display driver.

Suppose i use my PC microphone as a sound detector. so if i place the mic at my table and start talking, the LED (drive by LM3915) should be able do display according to the noise level.

But i dont know how to do all this..
what kind of circuit i need between the IC and the mic. also i need to cascade the LM in order to display 0-60dBSPL.
what i need here? rectifier? peramp?

 

[IanP]

lm3915 mic

To connect a microphone to LM3915 you will need a micophone pre-amplifier (see picture below) ..
How to cascade LM3915 for 60dB range you will find in LM's data sheet:
**broken link removed**
Regards,
IanP

 

[TOMIN333]

here is a simple audio level circuit using LM3915 IC

for circuit details, just goto

**broken link removed**

 

[flamesier]

can the output led be connected so that it can light up an ac bulb?
im trying with triac bt66 but the light wont blink according to the sound..
it stays on...somebody please help me...its quite urgent...