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closed loop to normal open transistor

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=78736
Printed Date: May 05, 2025 at 7:46 AM


Topic: closed loop to normal open transistor

Posted By: shaun gale
Subject: closed loop to normal open transistor
Date Posted: June 05, 2006 at 6:15 AM

hi i know this circuit circuit exists because i have used it before but i cant rember the values . i want to use the rear heated window element (closed loop ) to trigger an alarm with only n/o to ground inputs .i dont want to use a relay because of  the current  draw . i think the circuit i usedto had a tip 41c transister and adrop down resister .

thanks for your time




Replies:

Posted By: hotwaterwizard
Date Posted: June 09, 2006 at 10:33 PM
posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !



Posted By: hotwaterwizard
Date Posted: June 09, 2006 at 10:36 PM
You can use a TIP41 for the NPN but it only handles 6 amps with a heat sink the 2N2055 handles 15 Amps of current.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !



Posted By: shaunshow
Date Posted: June 10, 2006 at 4:42 PM

thanks for that . that should do the trick cheers





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