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

Master Category List - Dave's Circuits

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  Alarm Circuits

UNPLUGGED POWER CORD ALARM 


Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries. However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries. So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time. The device was designed to snap onto the outside of a power cord, where it senses the AC electric field emitted. No direct connection to the internal wires of the power cord is needed. I also included a low battery voltage monitor.

Click on Drawing Below to view PDF version of Schematic

Circuit Unplugged Power Cord Alarm designed by David A. Johnson, P.E.


More  Alarm Circuits

Master Category List - 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.