Telephone-sound-level-meter-monitor


Posted on Sep 25, 2012

The telephone-line decibel meter and line-voltage sensor shown lets you accurately monitor and adjust telephone sound levels. The 600-0 resistor properly terminates the line.


Telephone-sound-level-meter-monitor
Click here to download the full size of the above Circuit.

Power drain from the 9-V battery is 2 mA, and the meter provides ±30 dB range.




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