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Electronics => Beginners => Topic started by: yelneerg on March 30, 2016, 06:07:55 pm

Title: How to thermally connect a thermistor to a TO-220 component?
Post by: yelneerg on March 30, 2016, 06:07:55 pm
I want to build a circuit which reacts to temperature (which will be the topic of a different post) and it seems like I should go with a thermistor as the sensor but I can't seem to find any examples of how to thermally bind the thermistor to an IC. Specifically I want to track the temperature of a LM317. Should I use some sort of thermal paste that could double as glue? Or maybe put the head of the thermistor in a blob of solder on the metal flange of the IC (although that seems like it would cause an unwanted electrical connection)? Attaching it with an alligator clip is what I've been doing so far as I'm prototyping.
Title: Re: How to thermally connect a thermistor to a TO-220 component?
Post by: Seekonk on March 30, 2016, 06:37:52 pm
Epoxy thermistor into crimp lug and bolt it to the case.
Title: Re: How to thermally connect a thermistor to a TO-220 component?
Post by: dadler on March 30, 2016, 07:47:14 pm
Could use something like this, in addition to a bracket or otherwise for bolting to the component:

http://www.amazon.com/Arctic-Silver-Alumina-Adhesive-AATA-5G/dp/B0087X725S/ref=sr_1_2?ie=UTF8&qid=1459367137&sr=8-2&keywords=Thermal+adhesive (http://www.amazon.com/Arctic-Silver-Alumina-Adhesive-AATA-5G/dp/B0087X725S/ref=sr_1_2?ie=UTF8&qid=1459367137&sr=8-2&keywords=Thermal+adhesive)
Title: Re: How to thermally connect a thermistor to a TO-220 component?
Post by: yelneerg on March 31, 2016, 05:01:30 am
Do I not need to worry about keeping it electrically isolated?
Title: Re: How to thermally connect a thermistor to a TO-220 component?
Post by: digsys on March 31, 2016, 05:20:01 am
Quote from: yelneerg
... Do I not need to worry about keeping it electrically isolated? 
Normally no. From their specs - Layered composite of aluminum oxide and boron nitride  ,  Pure electrical insulator, neither electrically conductive nor capacitive
Or you can use something like this (if it is a TO220 type package) - they have excellent fast temp tracking
Title: Re: How to thermally connect a thermistor to a TO-220 component?
Post by: yelneerg on March 31, 2016, 06:21:05 pm
Oh nice, I didn't even know those existed.