Bench power supplies are available in variable or fixed voltage versions. A variable power supply will offer the ability to adjust the output, be that voltage, resistance, current or power and is ideal where versatility is required in an application, such as circuit testing. Variable power supplies have a feature called Current Limiting so it will shut down or limit current to the maximum rating. They normally have controls to allow the adjustment of current from zero to the specified maximum current which helps to protect components. Variable voltage supply means that you can also set the voltage used.
Bench power supplies are available in two different designs – Linear or Switching. In general terms: