I–V Graphs (OCR GCSE Physics A, Combined (Gateway Science Suite)): Flashcards
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What are the axes on an I-V graph?
What are the axes on an I-V graph?
Current (y-axis), potential difference (x-axis)
I-V graph gradient represents
I-V graph gradient represents
Resistance
Formula for resistance
Formula for resistance
Unit for resistance
Unit for resistance
Ohms (Ω)
What is an ohmic resistor?
What is an ohmic resistor?
A resistor where current and potential difference are directly proportional
I-V graph shape for ohmic resistor
I-V graph shape for ohmic resistor
Straight line through the origin
What is a non-ohmic resistor?
What is a non-ohmic resistor?
A resistor whose resistance changes depending on the current
Why does resistance increase in non-ohmic resistors?
Why does resistance increase in non-ohmic resistors?
Wire gets hot, metal atoms vibrate, causing more resistance
In how many directions does a diode allow current to flow?
In how many directions does a diode allow current to flow?
One direction only
When does a diode allow current to flow?
When does a diode allow current to flow?
When potential difference reaches threshold voltage
What happens to a diode above threshold voltage?
What happens to a diode above threshold voltage?
Resistance drops rapidly, current increases rapidly
What is the resistance of a diode in the opposite direction?
What is the resistance of a diode in the opposite direction?
Remains very high for all potential differences