I have a challenge at work to build a device to monitor the health of ceramic cartridge heaters, similar to this. It operates with an AC transformer and there are 5 heaters I'd like to monitor independently. The transformer operates on our 120V mains and is estimated to provide 1A to the heater.
First I picked up a non-invasive current sensor but in the limited testing I've done so far, I think the < 1A current and the gauge of the wires won't provide the necessary field needed for useful monitoring. Additionally I'd have to scale the device's 0-1V output to 0-5V logic of my microcontroller.
Then I thought about sticking an LED indicator inline with the heaters, like this one. This brings me to my main question: if I put this LED in series with the heater, as in Transformer > LED > heater, will the current drawn by the heater just burn out the LED? Would a resistor in the circuit allow the indicator to work properly without also limiting the heater and/or just melting?