86-87 - Circuits and V-I Graphs Flashcards
What does an ammeter measure?
Current in amps
Where should an ammeter be placed?
In series
What does a voltmeter measure?
Potential difference in volts
Where should a voltmeter be placed?
In parallel around the component being tested
How can you alter the current in a circuit?
Add a variable resistor
What is a V-I graph?
A graph showing how current varies with P.D
What is the relationship between current through a resistor and P.D?
Directly proportional
What happens to resistance with temperature increase?
Resistance increases with temperature
What is significant about the V-I graph of a diode?
High resistance in the opposite direction
Why do components in a circuit heat up?
Some electrical energy is transferred to heat energy
Link temperature, resistance, and current ( -> leads to)
Temperature increase -> resistance increase -> current decrease
What equation links PD, current, and resistance?
PD = current * resistance
What does a curve mean on a V-I graph?
Change in resistance
What does a steep slope mean on a V-I graph?
Low resistance
