For more information, contact:

Joe Monkowski Advanced Energy Industries, Inc 970.407.6252

Marna Shillman Advanced Energy Industries, Inc 970.407.6280 marna.shillman@aei.com

MARCH 16, 1999 — Advanced Energy Industries, Inc. (AE), has named William A. Ruff vice president of engineering for the company’s Voorhees, N.J. operations (AEV). In announcing the appointment, AE’s senior vice president and general manager of AEV, Jim Gentilcore said, “We’re delighted to have Bill joining us in New Jersey. I know everyone shares my high opinion of Bill. His depth and breadth of experience — both within and outside of AE — bring stability and strength to the position and make him a key contributor.”

At AEV, Ruff will be responsible for all engineering efforts including agile frequency and higher power RF as well as a broad range of matching network technology.

Ruff, who joined AE in 1990, has progressed in responsibility from product management to engineering management and most recently to managing the development of a new RF product.

Before joining AE, Ruff worked at Central Microwave Company, holding the positions of business development manager, operations manager, and division sales and marketing manager. Prior to that, he was with Tektronix, Inc., Sperry Flight Systems, and King Radio Corporation.

Advanced Energy Industries, Inc., is a leading developer and manufacturer of power supplies and related products that are critical in the manufacturing of semiconductors, data storage devices, flat panel computer displays, and other products using thin-film technology. Founded in 1981, AE is a publicly held company. Its stock is traded under the Nasdaq symbol AEIS. The Web site address is www.advanced-energy.com.