# Thermistor Experiment Essay

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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 (â„¦) and the equation for this is; Resistance (â„¦) = 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…show more content…
The voltage in a circuit gives the electrons the energy to move and as more voltage is applied and the potential difference across the atoms increases it gives the atoms that are not in the outer shells the energy to push against the force from the nucleus and effectively jump into the band of moving electrons in the outer shells. This applies to the band theory which explains why metals conduct electricity so easy, why insulators conduct virtually no electricity whatsoever and the behaviour of a thermistor. Between the conduction band (the band of freely moving electrons) and the valence band (the band on inner shell electrons) there is a gap that is know as the forbidden gap. No electrons can move through this gap and the only way electrons can pass from the valence band to the conduction band is by gaining enough energy to jump the gap. In metals the forbidden gap between the bands is extremely small and so it takes an extremely small amount of energy for the electrons to jump the gap as so electricity can flow very easily through all metals - this is why they conduct so well. In insulators the gap between the conduction band and the valence band is extremely large and almost no amount of energy given to