Temperature Control of a 3-watt Wirewound Resistor

In this video, we controlled the surface temperature of a 3-watt wirewound resistor by employing a feedback control loop that nudges the current through the resistor up and down while continuously reading a temperature sensor glued to the surface of the resistor. The current is supplied by the 9-volt battery shown through a Darlington-pair bipolar junction transistor (BJT) acting as a high-speed switch. The on/off state of the BJT is set by a pulse width modulation (PWM) signal from the 3.3 volt GPIO18 pin of the Raspberry Pi computer. The pulses are output at 100 Hz, and the duty cycle of the pulse signal controls the effective average current through the resistor. Please see my previously posted "Thermistors" article for further information on the temperature sensing hardware, Python program libraries, and interactive UI on the smartphone. The PWM signal is implemented using the gpiozero library that ships with the standard Raspberry Pi Python installation.

Видео Temperature Control of a 3-watt Wirewound Resistor автора Discovering New Places