MJLorton Solar Power and Electronic Measurement Equipment Forum
Older Technology => Older Technology => Topic started by: SeanB on August 07, 2014, 03:40:22 PM
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Thought I would share the inside view of an old thermocouple adaptor, made by Beckman.
I have had these for a good number of years, and they are still very nice to use with the original type K thermocouples, and proper thermocouple sockets. i have had to repair the thermocouples a few times as the tips burnt off.
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How does it work?
Amplifying the Seebeck- Voltage straight up to the needed level?
Or, it´s a chopper- amplifier? (That would be my guess. Also guess, I have detected a bridge- rectifier...)
Excuse the question. I´m more familiar with car-electrics, where generally NTC- Resistors be used.
Greetings,
Hartmut
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It is a straight thermocouple amplifier with linearisation and cold junction compensation. The diodes are a voltage doubler used to generate a -5V rail for the opamps inside. Mot of the magic happens inside a custom Beckman IC, the rest is just the conversion between C and F and the power supply.