The leakage current was too small to measure, showing the researchers had overcome the current loss issue in transistors. That might not sound fast by the standards of desktop PCs, which often run at speeds in excess of 2.5 gigahertz, but for control system applications it’s more than adequate. Lee predicts that switching speeds of a billion times a second (1 gigahertz) are possible. The faster the switching speed, the zippier the computing. At 550 ☌ Lee’s team managed to get the inverter to switch on and off 500,000 times a second &ndash performing a computation with each cycle. Like a telegraph operator’s Morse key, these levers physically make and break contact to pass or block currents.Īpplication of a voltage makes the levers move under electrostatic attraction. The device uses an arrangement of nanoscale levers instead of transistors. His team has developed a mechanical version of an inverter – the building block used to construct many types of logic gate, which themselves are a fundamental component of digital circuitry within computers. That prompted Te-Hao Lee’s team at Case Western Reserve University in Cleveland, Ohio, to consider returning to mechanical logic. Even silicon carbide, the semiconductor material hardiest against heat, doesn’t remedy the situation.
But above 250 ☌, the device becomes so awash with thermally generated electrons – even when it is supposedly off – that the voltage leaks through the gate to render the device useless. In a transistor, the voltage applied to one of the terminals, the gate, determines whether a current flows through it.
His unwieldy contraptions were superseded by electronic computers, through which data is transmitted via vast arrays of transistors in the form of varying voltages. It could therefore find uses in, say, jet and rocket engine electronics.īabbage famously designed mechanical computers through which data would circulate as steam-driven pistons turned cogs and levers. A DARPA-funded project has reinvented a type of logic gate in the style of Victorian inventor Charles Babbage – not for aesthetic reasons, but because the retro device works at temperatures too high for conventional transistors. Steampunk, the reimagining of modern day technology through a Victorian perspective, has found an unlikely follower in the US Defense Advanced Research Projects Agency (DARPA).
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