Chapter 14 - DC Circuits
Voltmeters are used to measure the potential difference between two points and ammeters are used to measure the current through it. The GCE A Levels requires us to understand how to connect these, and also how to deal with non-ideal voltmeters and ammeters. This video discusses these.
For the GCE A Levels, electrical earthing sets the potential at that point to be zero volts. This video will discuss how to analyse a circuit with an electrical earth.
This video introduces transducers, and will briefly describe the functioning of thermistors and light-dependent resistors (LDRs) as required by the GCE A Levels.
For circuit analysis in the GCE A Levels, we will need to study series arrangements. This video explains what a series arrangement is, and how we deal with the currents, potential differences and resistances in a series arrangement.
For circuit analysis in the GCE A Levels, we will need to study parallel arrangements. This video explains what a parallel arrangement is, and how we deal with the currents, potential differences and resistances in a parallel arrangement.
In the GCE A Levels, we can use the potential divider principle to make our circuit analysis more efficient. The principle basically states that for resistances in series, the ratio of the potential differences across them is equal to the ratio of the resistances.
This video will show 2 simple ways in which we use transducers in simple potential divider arrangements, to achieve create some practical circuits. The GCE A levels may require us to explain or design simple circuits like these.
In the GCE A Levels, you will be asked to analyse potentiometer circuits. This video explains the various components within the potentiometer circuit such as the resistance wire, the galvanometer, and also describes the unique things that happen at the balance point.
In the GCE A Levels, you will be asked to analyse current-voltage characteristic graphs (or I-V graphs) of various components. This video focuses on how to interpret the I-V graph of a filament lamp, or metals in general, and we will see that the I-V graph shows that the resistance increases as the potential difference across the filament lamp increases. The video will describe why this happens, including balancing the effects of increased thermal lattice vibrations and increased charge carrier concentrations.