Epoxying a 100 kΩ thermistor to a 909 Ω resistor (because I have a bunch of them) serves as a simple heater tester:
It dissipates 450 mW, raising the temperature enough to let the PWM control kick in, but not enough to get scary hot.
Some heatstink tubing prevents reduces the likelihood of horrible accidents involving the 20 V motor / heater power supply:
Keeping it under 50 °C seems like a Good Idea:
Not that I have a need to heat anything, but the MOSFETs work!
The Smell of Molten Projects in the Morning 
Comments
4 responses to “RAMPS 1.4: Simulated Heater”
What version of Marlin is that? It looks very old
Believe it or not, it’s 1.1.5, one epsilon behind the current head!
Almost not :) I did two 1.1.5s a few weeks ago and they look completely different :) Who knows what config options I flipped late in the night and blissfully forgot by the morning :)
I’m uncomfortable with the pace of Marlin updates, particularly given the wide variety of hardware it must handle; two successive
git pulloperations may produce firmware with entirely different foibles.