>In message <200003030151.OAA14047@mailhost.auckland.ac.nz>, Lance Allen > writes > >Interesting engineering point... > > > >I have just been a lecture by Alan Meier of Berkeley Lab, > >CA. He is basically proposing a world target of 1 watt > >standby for all appliances. > > > >What was interesting was that standby consumption is > >increasing dramatically for equipment, with some of the > >latest having almost no difference between on and "off". > >Alas this off power consumption is up to 6 watts for wall > >warts, 15 watts for TVs VCRs and 20 watts for > >Satellite/Cable boxes and Compact Stereos. Yes... those > >little stereos typ draw 20 watts on standby.... > >Satellite receivers don't actually go to standby, all they usually do is >turnoff the RF and video outputs, and any front display, and set the >receiver to one particular channel. Many newer VCR's have two standby >modes, a normal one where (like a satellite receiver) where very little >is powered down, and by pressing the button again they drop into a much >lower power mode where almost everything is shut down. > >As for stereo systems, buy a decent one with a mains on/off switch :-). It depends on the type of standby system used. The Denon amplifiers for example use a small (5VA ?) transformer to power up the micro which in turn controls the main transformer by relay. I'm not sure how much these units draw in standby mode but obviously must be less than 5VA. I've just been playing with a Sony DVD player & noticed that the PSU has two SMPS sections - one for the micro & one for the rest of the player. The micro controls the larger SMPS via an optocoupler. Maybe the ATX PSU's use a similar method - can't say I've had reason to look inside one - yet... Hi Fi systems have a standby mode mainly so the IR remote can power them up when the owners are too lazy to go over & push the power button. Hmmm - I think quite a few of us fall into that category ! OTOH, the cheap stereo systems switch the secondary only because it's cheaper than having a mains rated switch & the associated wiring & insulation requirements. It would be interesting to measure the "standby" power on various consumer products around the home - I think the results may frighten some of us ! I'm looking at designing some "multi-room" sound systems & one thing I was planning to do is put any unused (off) amplifier modules into standby mode. A lot of audio amp chips have this feature but hardly anyone ever uses it. Regards.. _______________________________________ David Duffy Audio Visual Devices P/L Unit 8, 9-11 Trade Street Cleveland 4163 Ph: +617 38210362 Fax: +617 38210281 _______________________________________