Wolfson Microelectronics, the Scottish maker of chips for many of the world�s must-have electronic consumer gadgets, said it had appointed Michael Ruettgers, former head of US digital storage giant EMC, to take over as chairman when John Carey retires at the end of the year.

Wolfson Microelectronics, the Scottish maker of chips for many of the world's must-have electronic consumer gadgets, said it had appointed Michael Ruettgers, former head of US digital storage giant EMC, to take over as chairman when John Carey retires at the end of the year.

Carey, who has been the chairman of Edinburgh-based Wolfson for almost seven years, will continue as a non-executive director, the company announced yesterday.

Ruettgers was chief executive of EMC from 1992 until 2001, when he became executive chairman and then chairman, before he left the group in 2005.

He is currently a non-executive director at Orvis, the US clothes company, and a lead independent director at the US defence contractor Raytheon.

Dave Shrigley, chief executive of Wolfson,which makes chips for iPods and a raft of other electronic devices, said Ruettgers would bring a "fresh, external perspective" to the company.

Wolfson, one of the world's brightest technology stars, has suffered recently as its rising revenues and assurances of double-digit growth have failed to impress investors and tens of millions of pounds have been wiped off its stock market worth in recent months.

Shares in Wolfson yesterday fell a further 1.6%, or 3.5p, to 217.5p, valuing the company at £256.4m.

Wolfson has prospered on the back of its contract to supply Apple's iPod music player and Sony's Playstation games console with its chips, but many industry observers have said the company has not built on that.

The company has won contracts to supply audio chips for Apple's much-hyped, recently launched iPhone.

It has also struck deals with South Korean mobile phone manufacturer Samsung Electronics, but analysts have said there have been too few other agreements with leading mobile phone manufacturers as they move into music-enabled phones.

Wolfson's chips are primarily used for tasks such as converting digital data into analogue signals for speakers and helping ensure that even tiny systems can meet sound standards set by demanding listeners.

The company also provides the chips for DVD players, Microsoft's Xbox games console, Sony's PlayStation Portable device, satellite navigation systems, flat-screen televisions, digital radios and cameras, as well as bluetooth headsets.