Series and Parallel curcits Flashcards
Explain why resistance increases with temperature
when an electrical charge flows through a resistor some of the electrical energy is transferred to heat energy and the resistor gets hot. This heat energy causes ions in the conductor to vibrate more and due to the ions moving about more it is more difficult for the charge-carrying electrons to get through the resistor. So because the current can’t flow as easily, the resistance increases.
complete this sentence: more current means an increase in
temperature, which means an increase in resistance, which means the current decreases again.
what does a series circuit look like?
all the different components are connected in a line, end to end, except from a voltmeter which are always parallel to the component.
If you remove or disconnect one component the circuit is broken and they all stop.
very few things are connected in series
What is the potential difference in a series circuit like?
In a series circuit the total potential difference of the supply is shared between the components. So the voltage round a series circuit always add up to equal the source voltage.
What is the current like in a series circuit?
The same current flows through all parts of the circuit and the size of the current is determined by the total potential difference and the total resistance.
What is the resistance like in a series circuit?
the total resistance is the sum of all the resistances, the bigger the resistance of a component, the bigger its share of the total pd.
What does a parallel circuit look like?
In a parallel circuit each component is separately connected to the +ve and -ve of the supply, if you remove or disconnect one of them, it will not affect the others.
this is how most things are connected.
What is the potential difference like in a parallel circuit?
the potential difference is the same across all components, all the components get the full source pd
What is the current like in a parallel circuit?
the current is shared between branches. The total current flowing around the circuit is equal to the total of all the currents through the separate components.
What are the two exceptions to the rule of series?
ammeters are ALWAYS connected in series even in a parallel circuit
Voltmeters are ALWAYS connected in parallel around a component even in a series circuit
What are the nine electrical hazards to watch out for at home?
- long cables
- frayed cables
- cables in contact with something hot or wet
- water near sockets
- shoving things in sockets.
- damaged plugs
- too many plugs in one socket
- lighting sockets without bulbs in
- appliances without their covers on
What are the three wires in a plug called, state their colours and what they do. Moving from left to right like in a plug.
Neutral wire- is blue
is always at 0V and electricity normally flows in and out through the wire.
Earth Wire- Green/yellow
protecting the wires and for safety by working with fuse to prevent shocks and fire.
Live wire- brown
main supply of electricity and alternates between +ve and -ve voltage.
How does a fuse and earthing work together to prevent electrical overloads?
If a fault develops meaning that somehow the the live wire touches the metal case because the case is earthed, too great a current flows through the live wire, down the case and down the earth wire.
This surge in current melts the fuse when the amount of current is greater than the fuse rating.
This cuts off the live supply and breaks the circuit so the whole appliance is isolated making it impossible to get an electric shock.
How should fuses be rated?
they should be rated as near as possible but just higher than the normal operating current.
What does RCCB stand for and what do they do?
Residual current circuit breakers- normally exactly the same current flows through the live and neutral wire but if somebody touches the live wire, a small but deadly current will flow through them.
This means the neutral wire carries less current than the live wire, the RCCB detects this difference in current and quickly cuts off the power by opening a switch.
