Standby current refers to the amount of current that a power supply draws when it is turned off by a control input (such as a remote) or when it is not supplying power to any load. Simply speaking, it is the electricity used by a device when it appears to be turned off.
Like the on power in a computer power supply, the current that electronic equipment draws when it is off is standby power. The standby current keeps the PS On voltage stable, making it easy to power on computers using the soft switch or keyboard. In addition, it enables the user to easily power on electronic devices, like a television set, using a remote control.
Legislation in Canada, the European Union, and the United States have significantly decreased the amount of energy wasted due to standby power. It is evident in new electronic devices, where it is brought down from approximately 50 watts to a mere 0.5 watts. The latest electronic devices, marked with IV, V, or VI, consume significantly less standby power. The power supply converting AC to DC and does not have the label, are probably the old ones. Also, a warm supply with a humming sound is an indication of standby power wastage.
Also See: What is Gassing Current?
Types of Standby Power
Basically, there are 2 types of standby power: on-call power and phantom power.
With the on-call power, devices can instantly deliver an energy service. It comes from the following devices:
- A constant LED or a digital display that requires power
- Devices with remote-controlled technology.
- Devices left on low-power standby, like printers and monitors.
Phantom Power refers to the energy that is wasted by devices using AC adapters. Some older devices can waste up to 50% of the supplied energy. It is also referred to as phantom load or vampire power.
Recommended: What is Reverse Current Protection?