Yes, a thermocouple is the proper sensor to use here, but a thermistor
will work just fine. In fact, all of the laser printers I have taken
apart in my successful quest to print directly on copper have used
thermistors as the temperature sensor in the fuser. Invariably just a
voltage divider with the voltage proportional to the temperature and read
by an adc. Very easy to implement and very accurate.
Mark
At 02:37 AM 1/2/2017, you wrote:
Mark
At 02:37 AM 1/2/2017, you wrote:
The transistor is being used as a diode. Iâve seen this on amplifiers to monitor the power transistors and adjust the bias so it donât go into thermal runaway. In all heater circuits I have dealt with we always used a temperature control with a thermocouple. These withstood the higher temperatures . they also had some form of high limit protection in case of a shorted thermocouple or controller failure.if the thermocouple failed open the controller simply shut the heat off altogether.
From: Homebrew_PCBs@yahoogroups.com [ mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Sunday, January 01, 2017 2:12 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: RE: [Homebrew_PCBs] Re: Temp upgrades of lam's HOW high is high heat conditions
A transistor with two of three legs soldered together makes a temperature probe. Is
the temperature inside of lam too hot? Google for temperature probe circuits like I
do for other projects.