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# Thermistors and sensitivity watch

1. To be frank, I'm crap at Physics and circuits.
Therefore, I need some help on planning out an experiment for school.
The experiment involves measuring the sensitivity of a thermistor at different temperatures - so I'm just going to measure the resistance at differnet temperatures, plot a graph and measure the gradient at various points, and show how the sensitivity changes.

However, I am absolutely useless with circuits. Can you tell me which circuit is right to measure the resistance or am I totally off it? Thanks!

The first one seems too simple. However, I don't know if you need a variable resistor or not - if you do - why do you need it?

I'll give + rep toooooo!
Thanks guys!
Attached Files
2. Which one.doc (25.0 KB, 174 views)
4. 2nd one.
5. (Original post by You Failed)
2nd one.
Why do you need a variable resistor?
6. (Original post by Narik)
Why do you need a variable resistor?

The 1st one.
7. (Original post by You Failed)

The 1st one.
Are you messing me around?
8. (Original post by Narik)
Are you messing me around?
What? How do you come to that conclusion? I said I read it wrong and corrected my answer....It's the first one you need to use.
9. Yeah its the first one. How are you going to go about heating it? And how will you measure the heat accurately at the thermistor?

If you'll be heating it to high temperatures where the resistance drops to zero ohms, you'll need the variable resistor to prevent the wire heating up. Depends on what voltage source you'll be using too though.
10. (Original post by JayEm)
Yeah its the first one. How are you going to go about heating it? And how will you measure the heat accurately at the thermistor?
Thanks - I'm just going to place the thermistor in water. As dangerous as that sounds, I asked my Physics teacher and he said it would be fine.
11. (Original post by You Failed)
What? How do you come to that conclusion? I said I read it wrong and corrected my answer....It's the first one you need to use.
Sorry!
Thanks though!
12. (Original post by JayEm)
Yeah its the first one. How are you going to go about heating it? And how will you measure the heat accurately at the thermistor?
The best way for the OP to do it, is heat it up to a desired temperature (I'm not sure what equipment they will have to do this) and then as the temperature drops, take the readings for the resistance. Much more accurate than heating while taking the measurements.

(I realise this doesn't actually answer what you were asking the OP, it was just a thought I'm contributing =P)
13. (Original post by You Failed)
The best way for the OP to do it, is heat it up to a desired temperature (I'm not sure what equipment they will have to do this) and then as the temperature drops, take the readings for the resistance. Much more accurate than heating while taking the measurements.

(I realise this doesn't actually answer what you were asking the OP, it was just a thought I'm contributing =P)
Thanks! I'm basically just going to do what they're doing in this video:

Easy and simple stuff.
14. (Original post by JayEm)
Yeah its the first one. How are you going to go about heating it? And how will you measure the heat accurately at the thermistor?

If you'll be heating it to high temperatures where the resistance drops to zero ohms, you'll need the variable resistor to prevent the wire heating up. Depends on what voltage source you'll be using too though.
I'm going to be placing only the thermistor in water. My maximum temperature is 90*C - I don't think this will bring the resistance to 0 ohms...will it?
Thanks.
15. (Original post by Narik)
I'm going to be placing only the thermistor in water. My maximum temperature is 90*C - I don't think this will bring the resistance to 0 ohms...will it?
Thanks.
I doubt it.

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