DTM7000
24
Doc.: 00293978-v1
Wiring diagram
The two metre wire is represented by the curved wire; its role is to supply the circuit. At the terminals the
voltmeter measures the voltage across the terminals of the wire.
What happens when a voltage is applied?
The bulbs light and the test conductor heats up.
Carry out a test with each wire, what can be deduced?
The longer and thinner the wire the greater the voltage drop across the terminals.
How does the voltage change once the circuit has been energised?
The voltage reaches a peak then first connected, then decreases over time.
How could one define the resistivity of the wire?
The resistivity of the wire has a positive temperature coefficient.
What impact will this change in resistivity have on the voltage and current in the line?
The voltage across the terminals of the wire reaches a peak when first connected then decreases over
time. The current follows the same curve.
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