Variant 3

Electrical current needs a PATH on which to travel. Another name for this path is a circuit.  Electricity flows from the power source, in a loop or a circuit, back to the power source. This means that the electricity must start and finish at the same power source. If the circuit is not complete (i.e. if the loop is not closed) then electricity cannot flow through it properly. Which one of these loops allows electricity to flow? Electricity flowing through a circuit is called a current.

A load is a device that uses electricity (like a buzzer of a light blub). The load needs electrical energy to be able work. The electric current from the power source flows from one place to another through the wire of a circuit.

A power source provides a steady flow of electrons. Larger appliances like heaters and large computers usually get their power from the mains.

Variant 4

Metal wires (conductors) are often wrapped in plastic (insulators) so as to stop the electric current flowing into objects that touch the wire.

If electricity flows through an object, then scientists say the object conducts electricity, and they call it a conductor. Metals are very good conductors. A small bit of energy is released as heat when electricity flows through the conductor. If electricity doesn’t flow through an object then scientists call it an insulator. Plastic, wood and rubber are all very good insulators. You can increase a circuit by increasing the length of the connecting wire. What do you think will happen to the light bulb as the wire gets longer? How about as the wire gets shorter?

Switches allow you control over the circuit. You can stop the flow of electricity by breaking the circuit. When the switch is in the “on” position the circuit is complete.

Variant 5

Switches allow you control over the circuit. You can stop the flow of electricity by breaking the circuit. When the switch is in the “on” position the circuit is complete. When the switch is “off” position the circuit is broken. Sometimes circuits are drawn using special symbols. These symbols make it faster and easier to draw circuits and once you understand what the different symbols stand for, these diagrams are very easy to understand.  However if you don’t understand what the different symbols stand for, then the diagrams look a little strange!

A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a light switch. Automatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position .

Variant 6

Whenever two components are joined together in the same circuit, there are two different ways they can be wired: in series or in parallel.

In the in series circuit the components are joined together in one bigger circuit one continuous loop. Electricity passes first through one component first then the next one. A disadvantage of the in series circuit is that when one component is foulty, the other components will stop working. A major advantage of parallel circuits is that if one component is foulty, the other continues to function.

Batteries can also be connected in parallel or in series. But, if you are using more than one battery in a circuit they need to all face in the same direction to work. If two batteries are connected in series, then the voltages add together. Adding more cells in a line (in series) will make the blub burn brighter.