This is the backup source of electrical energy that remains dormant and starts functioning as soon as a control device instructs it to.  

A fully charged battery ready to take over supplying a load in case of emergency.

An auxiliary source of power, intended to power timing and control circuitry in an appliance or electronic device, when power to primary operating circuits has been “switched off.”

This refers to an emergency power generator in the case of power failure during which the elevator car will typically lower to the lowest landing and open the doors and shut down. The elevator will re [..]

Standby power is the power consumed by an appliance or device when the device is not in use but is ready to be rapidly put into use. Standby power is also called vampire draw, vampire power, phantom l [..]

The energy used by appliances and electrical devices when they are turned off and not in use.