Charged up

Detection of electric charge has now been made simpler with the development of a new nanometer-scale mechanical electrometer. Consisting of three electrodes, a mechanical element which moves in response to the force experienced by the electrodes in the presence of charge and a displacement detector to monitor the motion. Developed by A N Cleland and M L Roukes of the US-based firm Caltech, the device has the advantage of being operational even at relatively high temperatures. In this it scores over the normally used single electron transistors which need ultra low temperatures for operation.