Current Electricty Flashcards
What is the equation linking energy current and time and voltage
Energy = current x voltage x time
What is the equation linking energy charge and voltage
Energy = charge x voltage
What is the equation linking charge current and time
Charge = current x time
What is resistance
Voltage over current
What is energy measured in
Joules
What direction does current flow
Positive to negative
What happens in a parallel circuit
Cell runs down more quickly
Voltage across each branch is the same as the supply
Current in branches equal that of supply
What happens in series circuit
Voltage across the circuit = supply
Current is the same everywhere
What is a straight line graph show
Directly proportional
Why does resistance increase with voltage and current
Lamp Gets hotter so it’s harder for the current to get through this increases resistance as the particles vibrate more and it’s harder for the electrons to flow through
What is an ldr
Light dependent resistor that resistance depends on the intensity of light falling on it an example is automatic street lamps
What is mains electricity
230 volts
What is a thermistor
Temperature dependent resistor as temperature increases resistance decreased
Example of thermistor
In fridges when the fridge gets to hot the thermistor will activate the circuit
What is a diode
Allows current to flow in one way only . If diode is connected wrong way no current will flow
How do u activate diode
Voltage of 0.7 v must bbe applied to the diode
What is a rhetostat
Type of variable resistor . Long coil of resistance wire with a sliding contact .
What happens as you bring in more cool on the rhetostat
More coil increases resistance and current goes down