According to the Energy Saving Trust, if you add up all the current drawn in standby mode by items such as stereos, TVs, VCRs and DVDs over a year in the UK alone, it amounts to 3.1 million tonnes of CO2 released into the atmosphere.This is without factoring in the current drawn by all the PCs,laptops and their associated peripherals left in standby mode. Circuit diagram : Green USB switch Circuit Diagram It is not necessary to spend a great deal of money or time to make a difference on a personal level. The circuit described here is designed for use by laptop or notebook computers. It will automatically switch off all mains powered peripheral equipment including monitor, printer, scanner, TV tuner and USB hub etc when it detects that the notebook is switched off. The circuit is quite straightforward; in addition to an optocoupler it requires a 12 V double-pole ...