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.

 

Circuits designed by David Johnson, P.E.
Last Updated on: Wednesday, October 18, 2017 05:04 AM

List of Dave's Circuit Designs

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  LED Circuits

Modified 4 D Cell LED Lantern (July 29, 2017 )
designed by David A. Johnson, P.E.

While shopping at a sporting goods store one day, I spotted a compact LED lantern.  It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles.  The LEDs were standard T 1-3/4 epoxy types.  The lantern had a three mode switch which selected between off, full power and half power modes.  At the half power mode, only half of the 21 LEDs were illuminated.  At full power all LEDs were illuminated.    All the LEDs were wired in parallel. The lantern was powered by four 1.5v D alkaline cells, making for a 6 volt supply.  I wanted to turn the lantern into one more useful, by converting the push button switch into a rotary dial to control the LED intensity.  I also wanted to power the light from four D size 10 amp hour NiMH rechargeable cells.

 

The first thing I did was dismantle the lantern and remove the control circuit.  I also replaced the 4 alkaline cells with rechargeable 10 amp-hour 1.2v NiMH cells, forming a 4.8v supply.  I designed a new control circuit, which used a variable resistor containing a switch.  When rotated fully counter-clockwise, the switch would click, turning off the LED.  When rotated fully clockwise, the light would be at full power.  I set the LED current control range from a low 1ma to a full 400ma setting.  The low setting would be great for a night light feature for inside a camping tent.  When fully charged the lanternís battery should operate the LEDs for 24 hours at full power and a year at the lowest power setting.  The circuit I used is shown below..

4 D Cell Camping Lantern 10 amp-hour D NiMH Cell
 
Click on Drawing Below to view PDF version of Schematic

More  LED Circuits

Dave's Circuits


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.