Raven Luni
- Oct 15, 2011
- 798
- Joined
- Oct 15, 2011
- Messages
- 798
Greetings,
I'm wondering specifically about the collector emitter path in a BJT when it is 'turned on'. Is this seen as a resistance or is it more like a diode voltage drop?
Why I'm asking: I have a bunch of cheap digital thermometers that I want to use as part of a thermostat system. Normally they'd be independent of any other circuitry (used for display only) but I've noticed a feature that I can make use of. Open and short conditions on the sensor (a thermistor) cause 'Lo' and 'Hi' to be displayed on the LCD respectively which could be used to report the 2 possible fault conditions (heater failure or thermostat failure). In order to do this, the thermistor path would have to go through at least 1 transistor during normal operation (likewise it would also be shorted by another transistor). Can this be treated as a normal conductance path or does it introduce other variables?
I'm wondering specifically about the collector emitter path in a BJT when it is 'turned on'. Is this seen as a resistance or is it more like a diode voltage drop?
Why I'm asking: I have a bunch of cheap digital thermometers that I want to use as part of a thermostat system. Normally they'd be independent of any other circuitry (used for display only) but I've noticed a feature that I can make use of. Open and short conditions on the sensor (a thermistor) cause 'Lo' and 'Hi' to be displayed on the LCD respectively which could be used to report the 2 possible fault conditions (heater failure or thermostat failure). In order to do this, the thermistor path would have to go through at least 1 transistor during normal operation (likewise it would also be shorted by another transistor). Can this be treated as a normal conductance path or does it introduce other variables?
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