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Circuits designed by David Johnson, P.E.
Last Updated on: Thursday, November 23, 2017 05:09 PM

List of Dave's Circuit Designs

Text & Graphics Copyright David A. Johnson, PE  --  ALL Rights Reserved.
LINKING to Dave's circuits is permitted but DO NOT COPY CONTENT to your WEB SITE server!




Telephone Circuits
 
Circuits Designed by Dave Johnson, P.E. :

Cell Phone Solar Powered Charger

Cut Phone Line Alarm

Display RF Signal Strength

DIY Cell Phone Charger

Do It Yourself Portable Cell Phone Charger

Four Line Telephone Line Status Indicator

Line Status Indicator for 1 Telephone Line

One-Line Telephone Line Status Indicator

RF 2.45Ghz Signal Detector

RF Signal Detector at 2.45GHz

Solar Powered Cell Phone Charger

Telephone Status Indicator for 4 Lines

Two Line Telephone Line Status Indicator
1 Line Telephone Line Status Indicator

2 Line Telephone Line Status Indicator

2.45ghz RF Signal Detector

4 Line Telephone Line Status Indicator

Alarm Sounds when Phone Line is Cut

Cell Phone Charger


 

Dave's Circuits

Hobby Circuits

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Copyright  January, 1998 - November, 2017     David A. Johnson & Associates.  All Rights reserved. 
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