A variable voltage power supply is an electronic device that transforms an input voltage into an adjustable range of output voltages. Different models have a set range of output voltages the user can choose from. Once you know the likely range of voltages you are going to need, you can then choose the appropriate unit to match.
This power supply can be used for many different purposes, and we will look at some of those uses next.
Many electronic products, especially portable ones, use a variety of voltages to power them. To do this, manufacturers often use batteries as the source of power. There are many different voltage batteries, and battery combinations for them to choose from. If the batteries in your device run out of power, you may not have the correct type ready for replacement. With a variable power supply on hand, you can provide the correct power to keep your device working. It can then be disconnected once you have the right batteries available.
Perhaps your batteries have not been in use for very long, and you suspect a fault in the electronic unit. With the variable power supply, you can now provide the power in place of the batteries. This will determine if the problem is with the unit, or its batteries.
Some electronic items use a lot of power, and cause batteries to quickly expire. If the replacement batteries are expensive, then using an adjustable voltage power supply may be more cost effective.
People involved in product repair and testing often use an external adjustable power supply to aid in fault finding. By using a variable voltage power supply, the output voltage can be slowly increased and help identify which components are beginning to fail well before any fuses blow.