- on Computer/Software/Internet
- Published in issue 7/2009 on page 120
PC Power Saver
This circuit is designed to help minimise the quiescent power consumption of PCs and notebooks, using just our old friend the 555 timer and a relay as the main components. The circuit itself dissipates around 0.5 W in operation (that is, when the connected PC is on); when switched off (with the relay not energised) the total power draw is precisely zero. A prerequisite for the circuit is a PC or notebook with a USB or PS/2 keyboard socket that is powered only when the PC is on.