Hi all. From: Bill Owsley Sent: Friday, August 24, 2007 5:40 AM
Have you ever reversed the current across one of these and noticed the junction gets cold? Actually, it gets hot! At least one of the materials gets hotter, and one gets cooler, the net effect being positive. If you make the junction from two plates, and stick a big heatsink on the hot material to try to keep it near ambient, then the temperature differential drives the cold side down of course. I used to use this XXX years ago to cool Infra Red Detectors to reduce the noise floor. And of course, the insulating boxes often described as 'Fridges' you connect to your car cigarette lighter socket to chill beers for the beach is little more than a Peltier device with a heatsink and 12V fan to keep the hot side cool. They can take 20 best quality amps from the battery, so you do this while parked at your peril, especially if you are the last one to go home. Reversing the polarity, usually by reversing the connector on the box, reverses the heat difference and the fridge becomes a cooker... This it is much better at, if 240 watts is enough to cook anything. Temp differentials they are good at, heat pumps they are not! Tuppence worth... Chris Duprés Chris Duprés Compliance Engineer Elekta Limited Linac House Fleming Way Crawley West Sussex RH10 9RR www.elekta.com tel: +44 (0) 1293 654311 fax: +44 (0) 1293 654260 *******************Internet Email Confidentiality Footer******************* The contents of this e-mail message (including any attachments hereto) are confidential to and are intended to be conveyed for the use of the recipient to whom it is addressed only. If you receive this transmission in error, please notify the sender of this immediately and delete the message >from your system. Any distribution, reproduction or use of this message by someone other than recipient is not authorized and may be unlawful. Elekta Limited is a company registered in England and Wales whose registered number is 3244454 and whose registered address is Linac House, Fleming Way, Crawley, West Sussex, RH10 9RR - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
