You will be left with the 1.5mA max supply current for the MAX6675. (since that is a CMOS input) there will hardly be any current drawn at all so * - The max output from the SO pin is 50mA but you won't design it thatīadly will you? If you feed the SO outpout into a normal microcontroller input Interface that provides the 12 output data bits.Ġ.25☌ Accuracy ( 20☌ to 80☌ ) (**) ☓☌ The output format of the MAX6675 is SPI - a digital clocked, read only, Type-K thermocouple trivial, as the above are included in the chip andĭon't even have to retrieve the analogue value the ADC generates aĭigital output which is transmitted as a 12bit serial sequence. You a in-built amplifier, Cold -Junction-Compensator (CJC) and an ADC. This is where the MAX6675 comes in as it has everything built-in Cold Junction Compensator (or an ice bath).That the full temperature reading is made available. compensate for the ambient temperature at the non-sensing end so This temperature, and add this voltage to the thermocouple voltage (you workīackwards to find the equivalent voltage when one end is at a temperature ofĠ☌) i.e. Thermocouple, and figure out the voltage that the thermocouple would have at You don't really want to mess around with an iceīath (unless you want better precision) so a technique calledĬold-Junction-Compensation (CJC) is used.īasically you measure the temperature of the (colder) end of the The generated voltage is extremely small (~41uV / ☌), and is different forĭifferent types of thermocouple, so an amplifier is required to turn the One side is magnetic while the other is not. Manganese, 2% aluminium and 1% silicon]] and and Alumel (Nickel Aluminium) [95% nickel, 2% Note: A Type K thermocouple is actually composed of Chromel
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