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

DiscoverCircuits.com has links to 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.

HOME Schematics Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches
Welcome to DiscoverCircuits.com - online since 2002

See Media Kit for
Advertising Opportunities

Attention Designers:  Please alert us by eMail if we have linked to sites
where your original material has been copied without your permission.
We will change to the LINK to your site.  
Thank you.

 

DiscoverCircuits.com -- Hobby Corner
Last Updated on: Monday, October 09, 2017 03:35 PM

Hobby Circuits' Circuit 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 Current Indicator Circuits

Battery Charge Current Indicator 7

This circuit was inspired by a company needing a DC current indicator light which was small enough to be molded into a medium size 28v rechargeable battery assembly.  They specified that they wanted the circuit to turn on the LED indicator light with 500ma or more of battery charge current.  When surface mounted components are used, the complete assembly should be smaller than a postage stamp. 

A LM4040 5 volt reference diode used both to provide a fixed 5v for the circuit and when divided down to just 5mv, it also serves as a reference to a low power voltage comparator.

A 0.01 ohm shunt resistor is used to sample the flowing current.  When the DC current into the battery reaches about 500ma, the voltage is sufficient to toggle the comparator, which turns on the green LED using a driver transistor.  The whole circuit draws about 140ua in standby mode, so it can be left connected to the battery. If you want to turn on the LED at a lower current level, you can easily change the value of the shunt resistor.  IRC makes some small surface mounted shunt resistors of various resistances.

 

Click on Drawing Below to view PDF version of Schematic

Battery Charger Indicator Circuit designed by David Johnson

Current Sense Resistor

Current Sense Resistor

More Current Indicator Circuits

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

 


Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



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


Discovercircuits.com endeavors to credit original designers.   Please alert us by eMail so we can
delete links to material that have been copied without your permission
.   Thank you.


Copyright of all original material on this website is the property
of David A. Johnson, P.E. (Dave Johnson & Associates ) unless otherwise noted.  

Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.
All material is provided "as is" without guarantees or warranty of any kind, either expressed or implied.