Can this power supply be used in both AC and DC applications, and how is the mode selected?

Yes, this power supply can be used in both AC and DC applications.

Questions & Answers: Analog Technologies Compact High Voltage Power Supply 0 to 25kV Output Voltage 0.5mA Output Current AC DC Converter AHVAC25KVR5MABT

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Analog Technologies Compact High Voltage Power Supply 0 to 25kV Output Voltage 0.5mA Output Current AC DC Converter AHVAC25KVR5MABT