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Subject: RE: CB 245 construction question
From: groski@esvax.dnet.dupont.com
Reply To: mapug@shore.net
Date: Thu Sep 22 08:38:29 1994

Robert, The 'Shacks sells ( or use to sell) a cheap ( about $15.00), small and thin multimeter that looked like a credit card. This would be the simplest solution. To build a circuit to read a voltage across the thermistor won't be to hard, the problem is that the resistance is not linear with temperature, so neither would be the voltage so you would need a micro controller with a fuction programmed in or a look up table to convert to a temperature reading.So a cheap digital multimeter that reads resistance plus a conversion table written on a piece of paper would be the simplest and cheapest solution. I do cryogenics as part of my job and I had some input to the design of the cooling system in the cookbook camera ( see acknowlegments ). Cooling is way oversized so adding the thermistor is not going to add much heat, just use fine wire ( wire wrap works great) to wire it up and don't leave the multimeter on all the time since it is passing a current through it which will heat the thermistor up a small amount after awhile. Dave