Thermistor Experiment

Thermistor Experiment

Aim: To investigate how the temperature affects the resistance of a

thermistor

Background Information:

The resistance determines the difficulty in which energy can pass

through a circuit. It is measured in Ohms (Ω) and the equation for

this is;

Resistance (Ω) = Voltage (V)

Current (I)

A thermistor is a type of variable resistor that's resistance is

affected by heat and in my investigation I am experimenting with the

manor in which temperate affects the resistance in a thermistor.

In Physics by Patrick Fullick it states that;

"[a thermistor] allows more current to flow as the potential

difference across it increases"

This is the exact opposite behaviour of a filament lamp which as the

potential difference increases the current is also allowed to increase

but as the potential difference begins to reach a certain level the

resistance increases and so the rate at which the current increases

slows down. In a thermistor the current increases as the potential

difference across it increases. This is because as the voltage

increases it creates more heat and the thermistor reacts to this by

decreasing its resistance and therefore allowing the current to

increase.

In an ordinary resistor the resistance increases as the voltage

increase. This is because as the potential difference across it

increase, the friction of the moving particles heats up the particles

in the resistor causing them to vibrate more. So as the particles

vibrate, they obstruct the electrons that are trying to pass through

more frequently and so a greater resistance is built up.

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a certain temperature, oil becomes quite dangerous to heat. If I did

this I would be a definite improvement on my result because it would

mean that I could investigate further on the behaviour of a thermistor

and try to find out at what temperature the thermistor I was using

reaches no resistance or the point at which the resistance across it

stops decreasing.

Apart from these points I think my method in my experiment was

effective and allowed me to obtain my results safely without too many

faults. The units in which I recorded my results were correct and

showed the results of the data I collected clearly so if I was to do

it again then I would keep the method and units in which I measure the

temperature and resistance the same; only changing some of the

equipment so that the data could be more accurate.