Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 30,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


DiscoverCircuits.com -- Hobby Corner
Last Updated on: Tuesday, April 01, 2014 04:33 AM

Hobby Circuits' Category List

The contents & graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB SITE server

More  Display Circuits

Isolated Power Supply for Digital Panel Meters
September 13, 2008

Many inexpensive digital panel meters, such as the one shown below, are designed to operate from a 9v battery.  However, the nature of the panel meter internal design often requires that the DC supply used to power the device be isolated from the ground terminal of the panel meterís input. 

This often makes it difficult to use with a common connection between a DC power supply ground and a sensorís circuit ground.  But, you can generate this floating voltage fairly easily using the simple circuit below.
This hobby circuit below is powered from a 12v to 15v supply and generates a 100KHz square wave signal, using a CMOS version of the 555 timer.  This AC voltage is rectified and limited to +9v using a charge pump method.  The two 0.01uF capacitors maintain a floating voltage for the panel meter, so its voltmeter ground input can also be connected to the DC power supply ground.

Click on Drawing Below to view PDF version of Schematic

schematic-isolated power supply for digital panel meters

More  Display Circuits

Hobby Circuits' Category List
eMail David A. Johnson, P.E. about this circuit

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Contact Info

 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy

Copyright  2002 - 2013 David A. Johnson & Associates.  All Rights reserved. 
 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.