This paper presents a study on several polysilicon TFT circuits that may be used for highly integrated electronic systems on flexible metal foils. The circuit performance presented here validates the polysilicon TFT metal foil technology as a suitable platform for the incorporation of control, processing and communication circuits onto a flexible system. This research addresses digital, analog and mixed signal polysilicon thin film transistor (TFT) circuits exploiting metal foil device assets, while complying with design and fabrication parameters of flexible substrates. This paper reports some of the highest electron mobilities recorded to date on TFTs fabricated on metal foils (over 300 cm(2)/V s) and presents data on high performance circuits including: shift registers running at speeds over 10 MHz, ring oscillators with stage frequency response over 1 GHz and mixed signal circuits for row and column display driving. This is one of the most comprehensive reports to date on general purpose circuits on stainless steel foils. (c) 2006 Elsevier Ltd. All rights reserved.