Resistors Flashcards
All 6 cards in this deck
What is an ohmic conductor?
A component whose current is directly proportional to the pd across it at constant temperature, so its resistance stays constant.
What happens to the resistance of a filament lamp as the temperature of the filament increases?
The resistance increases.
Why does the resistance of a filament lamp increase as the current through it increases?
A larger current heats the filament, and resistance increases with temperature.
What is the key property of a diode?
Current flows through it in one direction only; it has a very high resistance in the reverse direction.
True or false? The resistance of every resistor stays constant as the current changes.
False. For some (ohmic resistors at constant temperature) is constant, but for lamps, diodes, thermistors and LDRs it changes.
Name four components whose resistance is not constant.
Filament lamp, diode, thermistor and LDR.