[rcheshire (Rowland)]

Hi.

I'm working on a microcontroller setup for a small dew heater and wondering how much current a typical system uses.

The figures I came up with, indicate that 75mm of 22 gauge Nichrome wire requires 500mA for a 20C increase in temperature.
Increase in R with temperature is 0 for practical purposes.

I am interested in knowing what values others measure with their working dew heater. Parameters would be;

Nichrome wire length

Total resistance of the heating circuit.

Voltage across the Nichrome wire.

This will be very helpful to work out realistic performance and set more accurate parameters for the microcontroller PWM output, particularly as the dew heater will reference other temperature readings to set the correct temperature.

Many thanks

Rowland.