What are bench power supplies & sources?

Bench power supplies include test and measurement equipment. These devices provide direct (DC) voltage to equipment undergoing testing, such as circuit boards or other electrical products. These supplies often have positive, ground and negative voltage level output jacks, allowing them to supply varying voltage levels to different areas of a single or different circuits. Outputs of some types of bench power supplies can be stored in memory or controlled by a computer.

Although bench power supplies are similar to other AC-DC converters, they are higher performing. 

How do bench power supplies differ from average AC-DC converters and wall bugs?

Compared to average AC-DC converters, bench power supplies enable more controlled voltage and current parameters. Bench power supplies are also designed to be solid sources of power that do not interfere with the operation of the circuit, helping engineers focus on troubleshooting and design.

Bench power supplies are also unique in that they allow for greater protection through voltage limiting capabilities and tight voltage regulation while under load and transient load changes.

What are the different modes of bench power supplies?

Bench power supplies can operate under two modes including constant voltage and constant current. Constant voltage means that voltage levels can be maintained constant regardless of the load resistance. Similarly, the constant current mode ensures the same current is maintained regardless of changes in load resistance.