Over 40 Years of High Voltage Solutions


John Yakura 1932-2021


John passed from this life on Saturday, March 13, 2021.

John was a great friend and mentor – remarkable in every way, brilliant, good, kind – the list of excellent qualities goes on and on. I worked for the company that he, Erik Halleus, and Ed Marue founded in Visalia in the early 1970s. After their company, HVD, was sold, John joined Ken Haag and me to start a new company, Voltage Multipliers, Inc.

I have had the great honor to partner with John and live life for more than 40 years not only as a partner, but also a friend. He never sought to be noticed or recognized as someone important but without him, VMI would not have succeeded.

I will never forget the trust and commitment that we had. Without him, VMI would not have succeeded.

His wife, Chiz, his daughter Stephanie, and his son Brian are wonderful people that have lost a husband and a father – my prayers are with them.

Hundreds of VMI employees, past and current, know that he made his life matter greatly. He left a legacy that is of the highest quality and he was loved by all who knew him. I don’t recall ever hearing anyone speak badly of him.


Rest in peace, my friend.

Dennis Kemp


VOLTAGE MULTIPLIERS INC. was incorporated in December 1980 to design, manufacture and market high voltage semiconductor products. VMI initially designed and produced high voltage multipliers. The addition of high voltage diode manufacturing capabilities led the way to expanding our facilities and product lines to include custom high voltage power supplies.

The nature of VMI’s business requires a high degree of engineering service and follow-up customer support. VMI’s products are custom designed for military, industrial, medical, aerospace and other high-reliability applications operating at the leading edge of known technology.

The general market for VMI products is semiconductor power conversion devices, assemblies and systems. VMI has developed some of the world’s fastest switching rectifiers, and our growing product line of custom high voltage power supplies is being utilized in various applications worldwide.

When you look for high voltage power supply designers, important things to consider include the company’s methods of design verification, prototype capability, design-for-manufacturability skills, the ability to transition from prototype to production scale, and standard and custom testing.

At VMI, we are committed to quality and service. We are here to assist you throughout the production process, from design development to production manufacturing. We offer extensive testing, design verification, production support and custom design services.

All of VMI’s products are made and 100 percent tested at our facility in Visalia, California, USA.