One of the best ways to learn about circuits and resistance is by building circuits - either in the classroom or using an online simulation. I've previously recommended PhET DC Circuit simulation, which (despite some non-standard circuit symbols) is still a great way to take measurements that demonstrate concepts such as Ohm's Law. You can … Continue reading Online Circuit Simulators
Auto-electric?
We all know that fossil fuels are bad for the environment and that their use in cars is being phased out but how much do you know about the alternatives? Electric cars probably spring to mind but what about other options that might actually be better choices? This is relevant for the GCSE course and, … Continue reading Auto-electric?
Microphones and Loudspeakers
There is a great cross-over between two topics, waves and electricity, when we come to moving-coil microphones and loudspeakers. This pair of devices can be thought of as the sound-wave equivalent of motors and generators. Motors turn electrical energy into kinetic energy whereas generators turn kinetic energy into electrical energy. Similarly, microphones turn sound waves … Continue reading Microphones and Loudspeakers
Transformers
The famous "electricity war" between Edison and Tesla wasn't just about electricity generation, it was also about electricity distribution. Edison's DC electricity couldn't be sent very far due to power losses but Tesla's AC could go much further and benefit people over a much wider area. Efficient electricity distribution relies on minimising power loses due … Continue reading Transformers
Electricity and Magnetism
Whenever a current flows through a wire, it creates its own magnetic field. This may be surprising given that copper, which is normally used for electric wires, is not a magnetic material, but it is true nevertheless. This fact was discovered almost exactly 200 years ago by the Danish physicist, Hans Christian Oersted and led … Continue reading Electricity and Magnetism
Magnetic fields
Magnetism is a well known effect that was observed in nature thousands of years ago. In fact, the word "magnetic" comes from the region of Greece where materials that could attract and repel each other were first discovered: this region was called Magnesia. The knowledge you need to have about magnets is very straightforward but … Continue reading Magnetic fields
Electric fields
A field, in physics, is a region of space where one object can affect another object without the two objects touching each other. The most familiar fields are gravitational and magnetic but now we need to gain some understanding of electric fields and their shapes. Let's start with a quick recap of what we know … Continue reading Electric fields
Correct wiring of a 3-pin plug
There once was a time when the ability to wire a 3-pin plug was an essential skill - but not any more. For reasons of safety, many devices are now fitted with molded plugs that cannot be opened or removed. Nevertheless, the exam board still expects you to be able to identify the essential features … Continue reading Correct wiring of a 3-pin plug
DC and AC Electricity Pt2: Seeing the Difference
We commonly use meters to make measurements in electric circuits but meters are relatively simple devices and if the property we are measuring changes over a short period of time then a meter will not show this clearly (if at all). But a different instrument, the oscilloscope, has the power to reveal such changes in … Continue reading DC and AC Electricity Pt2: Seeing the Difference
DC and AC Electricity Pt1: Electron Movement
One of the most famous technological "wars" was the battle that raged almost 150 years ago between Thomas Edison's DC electricity and Nikola Tesla's AC electricity. For our purposes, we will put aside the stories of the two men (Edison was an inventor and businessman whereas Tesla was a scientist and idealist) and focus on … Continue reading DC and AC Electricity Pt1: Electron Movement
Mr Tarrant's physbang 'blog 