Testing Components Flashcards

All 3 cards in this deck

A power supply has only fixed whole-number output voltages. Which component can be added, and where, to give a continuously variable potential difference across a lamp?

A variable resistor (rheostat), connected in series with the lamp / power supply.

What are the steps to investigate how the resistance of a thermistor varies with temperature?

e.g. an NTC thermistor in a water bath

1. Connect the thermistor in series with an ammeter and supply, with a voltmeter across it.
2. Put it in a water bath and record current, p.d. and temperature as the water cools.
3. Calculate $R = V/I$ at each temperature and plot resistance against temperature.

Why is a fixed resistor connected in series with a diode when investigating how its current varies with potential difference?

To limit the current, protecting the diode from overheating and being damaged.