potential difference and resistance + component characteristics Flashcards
define potential difference
measurement of the difference in electrical potential energy between two points in a circuit.
potential difference equation
potential difference across a component, v (V) = energy transferred, E (J)/ charge, Q (C)
define resistance
measurent of how much a material tries to stop electricity passing through it
resistance equation
resistance, R (Ω) = potential difference, v (V)/ current, I (A)
what is ohm’s law
current is directly proportional to potential difference at constant temperature
what happens when you reverse the potential difference across a resistor
reversing the potential difference across a resistor reverses the current through it
the steeper the gradient of a graph…
the lower the resistance
for a bulb…
as the pd increases the temp of the lamp increase + the resistance
for a diode…
as the pd increases the resistance decreases to a very low value
for a diode (reverse direction)…
the resistance of the diode is v high and no current flows
for a light dependant resistor…
resistance decreases when light intensity decreases
for a thermistor
resistor decrease when temperature decreases
