Overview
A hotend melts filament in a controlled thermal zone while keeping heat away from the cold side.
3D Printer Hardware
Hotend basics: what each component does
Understand the heater, thermistor, heatbreak and nozzle before modifying a printer.
Heater and thermistor
The heater adds energy; the thermistor lets the controller estimate temperature and regulate it safely.
Before upgrading
Confirm voltage, sensor type, physical fit, wiring and safe temperature limits.