How to Make a Thermocouple Meter with the LTC2492

Thermocouples are perhaps the most common temperature sensor in use. And while they are extremely simple and rugged, the output is very small - tens of microvolts per degree Celsius. Traditionally, thermocouple measurement circuits use a cold junction compensation circuit to drive the thermocouple negative terminal and a low offset amplifier with enough gain to use the entire input span of a 12- or 16-bit ADC. Linear Technology’s LTC2492 greatly simplifies thermocouple instrument design. A simple filter and protection circuit is all that is required to build a rugged, ready-to-use meter. Some software tricks take care of cold junction compensation and the thermocouple’s non-linear output.

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