Diodes are electronic components that ... You should be able to recognise the graph of current against voltage for a diode. The diode has a very high resistance in one direction.

A voltage reference (also called a band-gap reference) provides the same functionality as a Zener diode, yet requires far less current to maintain a more-accurate voltage. While a Zener diode uses ...

Components which show I–V graphs that are not straight lines are non-linear circuit elements. The current through them is not directly proportional to the potential difference across them.