W Richards Worthing High School 23/02/2019 Electrical Circuits W Richards Worthing High School

Drawing Circuits 1) A cell, a bulb and a switch “in series” 23/02/2019 1) A cell, a bulb and a switch “in series” 2) A battery of cells, a switch and two bulbs in series

Measuring electric current 23/02/2019 We can measure the amount of electric current flowing through a circuit using a device called an “ammeter”. A

Current in a series circuit 23/02/2019 If the current here is 2 amps… The current here will be… The current here will be… And the current here will be… In other words, the current in a series circuit is THE SAME at any point

Changing the current 23/02/2019 If a battery is added the current will ________ because there is greater _____ on the electrons If a bulb is added the current will _______ because there is greater ________ in the circuit

Changing the current 23/02/2019 If a battery is added the current will ________ making the bulb ______. If a bulb is added the current will _______ because there is greater ________ in the circuit resistance decrease brighter increase

Parallel circuits 23/02/2019 A parallel circuit is one where the current has a “choice of routes”:

Current in a parallel circuit 23/02/2019 A PARALLEL circuit is one where the current has a “choice of routes” Here comes the current… Half of the current will go down here (assuming the bulbs are the same)… And the rest will go down here…

Current in a parallel circuit 23/02/2019 If the current here is 6 amps And the current here will be… The current here will be… The current here will be… The current here will be…

Advantages of parallel circuits… 23/02/2019 There are two main reasons why parallel circuits are used more commonly than series circuits: Extra appliances (like bulbs) can be added without affecting the output of the others If one appliance breaks it won’t affect the others either

Words – large, harm, safety, melt, live, circuit, fuse Fuses 23/02/2019 Fuses are _______ devices. If there is a fault in an appliance which causes the ____ and neutral (or earth) wire to cross then a ______ current will flow through the _____ and cause it to _____. This will break the _______ and protect the appliance and user from further _____. Words – large, harm, safety, melt, live, circuit, fuse