<P> Current can be measured using an ammeter . </P> <P> At the circuit level, there are various techniques that can be used to measure current: </P> <Ul> <Li> Shunt resistors </Li> <Li> Hall effect current sensor transducers </Li> <Li> Transformers (however DC cannot be measured) </Li> <Li> Magnetoresistive field sensors </Li> </Ul> <Li> Hall effect current sensor transducers </Li>

Why do current and electrons flow in opposite directions