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Circuits designed by David Johnson, P.E.
Last Updated on: Friday, November 17, 2017 06:32 AM

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More  Indicator Circuits

4 LINE TELEPHONE LINE STATUS INDICATOR
 

Many home businesses use multiple phone lines. This circuit gives you a visual indication when a line is in operation. The two AA battery cells should provide enough power for about one year of operation.

Click on Drawing Below to view PDF version of Schematic

Circuit 4 Line Phone Statue Indicator designed by David A. Johnson, P.E.

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