Cold Finger - check a few details

[Stub Mandrel]

I'm getting ready to look at a cold finger for my 450D.

If I use a nichrome loop to heat the front of the sensor, what sort of current/voltage is needed and what's the best way to fix it?

What about popping in a fresh silica gel packet at the start of each session instead?

[Adam J]

I would take a guess that you would want to dissipate around 0.5 watts across the nichrome wire in contact with the sensor cover glass. Remember that your have to also account for the resistance of the rest of your circuit. I would incorporate a potential divider to allow you to adjust the power.  

I would probably fix it to the perimeter of the sensor window using a very very small amount of silicon applied using the tip of a pin. Quite a tricky job. 

I would make it a full spectrum modification so that you can remove the filter holder from the front of the sensor unit. 

This is why i chose to use a sealed cool box rather than a cool finger. Mind you its possible to combine both concepts. 

 

[Stub Mandrel]

Thanks Adam, 0.5W is a handy ball park.