I want to monitor the temperature of a large peltier element's heatsink to control a fan. I think I'm going to use a DS18B20.
The 3 pin TO-92 looks like it's plastic, so I'm already worried about low thermal conductivity.* However, how should I secure this to ensure that the chip has the best thermal conduction? Thermal paste crossed my mind, but it'd be pointless to add that with plastic unless there is a big gap there.
I haven't picked out a heatsink yet, but there are plenty of them with a fairly large, flat surface that I could attach the sensor to if I needed. However, I can't glue it onto the heatsink because most glue doesn't conduct heat.
*They make thermally conductive plastics that can insulate (electronically), so the point about the plastic might be moot.
Best Answer
That is one poorly defined data-sheet, there is no mention of thermal issue on what is a temperature probe! However, there is this link to the thermal aspects of these one wire devices which give you thermal conduction coefficients. This takes you through self heating effects. Your device is actually listed.
Now all they need to do is give you the thermal mass so you can estimate the response time ...
I suspect that you'll just have to measure that. But if you are attaching to a large thermal mass as it is, that mass will dominate.
You can get thermally conductive epoxies made specifically for this task, and bond the flat side down to your plate.