[Music] ever wondered how we generate electricity I have two strong magnets and a coil of wire connected to an LED now this led has two different colors depending on the direction of the current when I move the magnet into the coil the LED lights up that's right I'm generating El electricity just by moving the magnet now if I switch the magnet around my LED lights up green now if I shake the magnet back and forth I get both colors I am actually producing an alternating current now this is not much different to how electricity is generated yes scaled up and much more efficient but generators work under the same principle by the relative motion between wires and magnets now we rely on electricity for our light in cooking in fact pretty much everything whether it is from non- rable sources such as cide and nuclear power plants or renewable ones such as wind and hydroelectric would you believe that much of our electricity comes from Simply moving Loops of wire between magnets or more efficiently by rotating them now here is a model generator in this case my wire is looped as a coil and this coil is situated between two mag magnets now watch when I move them by rotating them in between the magnets and just like my earlier demonstration I am generating an electrical current so how does it work it was Michael Faraday in 1831 who determined that moving a magnetic field across wires or more correctly causing a rate of change of flux you generate an electromotive force or EMF short now EMF is an archaic term and it's actually a voltage but what is flux now I have a more detailed explanation of flux in this video and I encourage you to check out my website which has a lesson on magnetic flux now I'm using a very simple model here of our generator here are our magnets and I have my Loop of wire in essence flux can be thought of of how much of the magnetic field is passing through the area of the loop so in this position I have a lot of magnetic field lines passing through so the flux is at a maximum in this position less lines pass through and so I have less flux and of course in this position no lines pass through the loop at all and so the flux is zero but it's the changing flux that causes a generation of a voltage and I can do this by simply rotating it like so and the faster I turn it the faster that changes and the greater the voltage is induced and if this Loop of Y is then connected to an external circuit and it's closed we not only induce a voltage but an electrical current back to my generator which is now connected to a Data Logger so we can record the current now as I rotate you can see that the current alternates positive then negative and back to positive and so forth and I'm producing an alternating current or AC for short if I spin it faster the frequency of this alternating increases but importantly so does the rate of change of flux and so I produce a higher voltage and this leads to a higher current this is how much of our electricity is generated scale this up and then drive the spinning not by hand but by other means and we produce the alternating current Supply we are familiar with and this is what coal or nuclear fishion is used to heat up water to generate Steam and to drive the generator turbines and in the case of wind turbines it's the wind itself that turns the generators and with hydroelectric it's the moving water through dams and so that explains alternating current but can we produce a direct current or DC the answer is yes and all we need to do is somehow switch the current every 180° degree turn now in the alternating configuration the coil is connected to an external Circuit by way of what's referred to as slip rings for a DC configuration we connect the coil to what is called a split ring commutator which flips the current every half turn and the result is that every half rotation the voltage and therefore the current maintains a constant Direction and therefore we have a direct current now let's see this in action at the moment it's in a slip ring configuration and by sliding this across it now becomes split ring and so let's see what happens we get direct current now I hope that has helped you have a greater understanding of how generators work check out my lesson on generators on my website where you can have a play with some of the interactives and as well have access to many other physics lessons now I value your support so please consider by buying me a coffee my name is Paul from physics High bye for now