ELECTRICITY Flashcards
The greater the resistance across a component….
the smaller the current that flows( for a given potential difference across the component
CHARGE FLOW =
CURRENT* TIME
Q=IT
POTENTIAL DIFFERENCE =
CURRENT * RESISTANCE
V=IR
factors that affect resistance
length
if the circuit is in series or parallel
what type of resistance do ohmic conductors have
they have a constant resistance
Does the resistance of ohmic conductors change with current
No
when an ohmic conductor is at a constant temperature
the current flowing through it is directly proportional to the potential difference flowing through it
what is an LDR (2 points)
an LDR is an light dependent resistor that is dependent on the intensity of light.
what happens to the resistance of an LDR in bright light
the resistance falls
what happens to the resistance of an LDR in darkness
the resistance is highest
what can you use LDRs for
automatic night lights
outdoor lighting
burgular detectors
what is a thermistor
A thermistor is a temperature dependent resistor
what happens to the resistance of a thermistor in hot conditions
the resistance drops
what happens to the resistance of a thermistor in cool conditions
the resistance goes up
where can you use thermistors
they can be useful temperature detectors
car engine temp sensors
electronic thermostats
how are the components connected in a series circuit
the components are connected in a line, end to end between the power supply
the voltmeters in a series circuit are always connected in PARALLEL
what happens if you disconnect one component in a series circuit
the circuit is broken and they all stop
Potential difference is _________________ in a series circuit
the Potential difference is shared between the various components
potential difference in a series circuit will always add up to the __________
the source potential difference
Equation for potential difference connected in series
Vtotal= V1 + V2 + V3 …..
Current in a series circuit is ________
the same through all components
Equation for current connected in series
I1=I2=I3=I4
In a series circuit the total resistance of two components is the _______ of their resistances
sum