A Microammeter Thermometer

I wanted to familiarize myself with Microchip’s MCP9700 thermistor ICs for some upcoming projects that require temperature measurement / compensation.

I decided to build a simple circuit around the MCP9700 to convert an old analog micro-ammeter into a thermometer for the lab. It displays 1uA per degree Celsius, has an output of 1mV per degree Celsius for external temperature monitoring / data logging, and draws only 20uA from a 5V supply.

The analog thermometer reading 20 degrees Celsius in the lab

The analog thermometer reading 20 degrees Celsius in the lab

Not only is it a cool looking centerpiece (I’ve always found old analog meters absolutely beautiful), it’s quite useful too!

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