In some texts, the interquartile range is defined differently. It is defined as the difference between the largest and smallest values in the middle 50% of a set of data. To compute an interquartile range using this definition, first remove observations from the lower quartile.
A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal.
Electromechanical relays comprise one or more electrical contacts having a mechanical movement, these being coupled to a moveable element of the magnetic circuit of an electromagnet. When the main current exceeds the specification, the output voltage of the current transformer activates the relay and the protective circuit.