You need to be able to calculate values such as power [power: The rate at which energy is transferred or work is done, measured in 'W'. Power = work done ÷ time taken. ], resistance [resistance: The opposition in an electrical component to the flow of electricity through it. Resistance is measured in ohms. ], circuit outputoutput: the term denoting either an exit or changes which exit a system and which activate/modify a process, and current gain [gain: the amount of amplification of the input voltage - ie how much bigger the output voltage is compared to the input voltage ].

There are a number of formulae to help you with these calculations, and you need to be familiar with these. You don't necessarily need to learn them, as you will usually be given a formula sheet in your exam.