Electrical measuring instruments:
Quantities of electrical current, voltage and resistance are measured using instruments called meters. Until the advent of electronic displays and semiconductor components, meters comprised a movement, working on the motor principle, driving a needle across a scale. These types of meters were called 'moving coil meters' or 'analogue meters'. Moving coil meters will be studied in some depth later in the course, because the principle behind their operation is the same as the principle employed in many aircraft instruments.
Modern meters are referred to as a 'digital meters' or 'digital voltmeters', more commonly abbreviated to DVM's, although they measure far more than just voltage. Digital meters are cheaper, more reliable, more robust and generally considered more accurate than their analogue counterparts, although some would argue that, used correctly, an analogue instrument is just as accurate.
It is essential that you are confident in the use of both types of meter. There are instances where a digital meter cannot be used, leaving no choice but to revert to an analogue meter.