Electricity Flashcards
What do switches do?
They used to turn circuit on (closed) or off (open)
What is a lamps function?
An electrical current heats the filament in a bulb so that it gives out light
What is the function of a fixed resistor? And what is its resistance like ?
It restricts or limits the flow of electrical current and it has an unchanging resistance
What is the function of a variable resistor?
By moving the position of the slider, it changes the resistance
What is the function of a thermistor ?
The resistance depends on the temperature as the temperature increases the resistance decreases
Tell me about resistance in a light dependent resistor
Resistance depends on light low light levels, high resistance
What does a diode do?
It allows current to only flow in One Direction. It is used to convert an alternating current into a direct current.
What is a direct current?
When the flow of electrons is in one direction
What is alternating current?
When the direction of electron flow continually reverses
Where should the ammeter be placed in order to measure current?
In series of that component
What is electric current ?
The rate of flow of electric charge
What is the equation linking charge time and current?
Charge=current x time or Q= I x T
What is charge measured in?
Coulombs (c)
What is current measured in?
Amps (A)
What is potential difference also referred as?
Voltage
How do you measure potential difference?
You place it in parallel to the component
What is potential difference?
A measure of energy per unit of charge transferred between two points in a circuit
How do you measure potential difference using energy and charge?
Energy divided by charge or E divided by Q
How do you measure potential difference using current and resistance?
Current x resistance
What is resistance measured in?
Ohms
Finish the sentence: one volt is the potential difference when one coulomb of charge transfers
One joule of energy
Do conductors have a higher low resistance?
Low
What is the current like in a fixed resistor?
Directly Proportionate to the potential difference
What is the current like in a Filament bulb?
It doesn’t increase as fast as the potential difference
What does more energy mean in terms of resistance in a filament bulb?
The resistance of the bulb increases
How does the resistance increase in a filament bulb when the temp is increased?
A higher temp increases vibrations of ions in the filament making it harder for the electrons to pass through
What happens if the potential difference is arranged to push the current the wrong way (reverse bias) in a diode
No current will flow
When will current flow in a diode?
If the potential difference is forward biased
1 amp = 1….
Coulomb Per second
What are the properties of a series circuit?
The current is constant potential differences shared between components and the total resistance is equal to the all of the individual sums of resistors
Give properties of parallel circuits
Components connected alongside each other. An electron won’t pass through every component of its way round. Current will split as it passes through one or other of the loops so ammeters are placed in different places. Potential differences equal to the potential differences cross the parallel components resistors are connected in parallel. The supply current is divided between this means the overall current is reduced due to having multiple paths
In a series circuit, the resistance of the network is equal to the sum of two individual….
Resistances
In parallel circuit, the resistance of the network is less than neither of the two….
Individual resistances
What is power?
The amount of energy transferred each second between the energy stores
What are the two equations for power?
Current times potential difference and current squared times resistance
One watt equals one…. Per second
Joule
How can electrical power be delivered?
With a low current and high voltage or a high current and low voltage
What does transmitting energy at a high voltage and low current due to the wire?
It keeps it cool and wastes less energy
