Adjustable Power Supplies

Adjustable power supplies, also called bench power supplies or variable power supplies, are must-have items to test and develop electronic components or circuits. They give users the ability to deliver a set voltage or a set current alongside the freedom to vary either in a moment.

AC or DC

While most adjustable power supplies are DC power supplies, variable AC power supplies do exist. These are useful when testing AC equipment, especially to evaluate the equipment's performance in under- or over-voltage conditions. This type of power supply can also bring AC voltage up to normal levels when line voltage is low. Like AC power supplies, DC models also plug into the main AC line. However, output is converted to DC.


The two types of variable power supplies are constant voltage types and models that also supply constant current. The former only gives users the ability to deliver a constant voltage, which can be adjusted as needed. They are designed to maintain voltage at the set level, irrespective of the load's resistance. Constant current models add the option to deliver constant current as well. In this mode, the power supply maintains the current at its set value irrespective of the load's resistance. Lastly, you can also find multiple output supplies. These offer more than one output, with the ability to set each one independently.

Important Power Supply Features

Some models allow users to set upper voltage limits, a useful feature when testing sensitive circuits. While all models feature positive and negative terminals, some also provide a ground or earth terminal. Moreover, some models offer terminals that allow users to connect an independent multimeter to view more accurate information regarding current and voltage. Some models allow master/slave connections, meaning they can be connected to other supplies to increase voltage and current capabilities. Lastly, some complex power supplies are programmable and usable in computer-operated environments.

Other Useful Bench Equipment

When testing and developing electronic components, users often need more than just a power supply. For example, signal sources are essential to test a component's response to different intensities of a given signal. You can further enhance them with signal source parts and accessories, thereby adding more functionality to a component.