On May 27, 11:19 am, Doug McNutt <[email protected]> wrote: > w_tommust be using the 200V figure to represent the peak to peak voltage > of the square wave. That's the difference between minus 100 volts and plus > 100 volts with respect to the common wire and is what one would measure > with an oscilloscope. > > The 120 volt value is called an RMS, for root mean square, ...
120 VAC appears as a sine wave peaking at 170 volts. Typical computer grade UPS outputs 120 VAC by adjusting the width of a 200 volt square wave. Whereas this UPS output is not destructive to more robust computers, this same voltage can be harmful to small motors and power strip protectors. To make a UPS cheaply, 'dirty' electricity such as 200 volt square waves and spikes up to 270 volts is acceptable - because it is not destructive to computers. However this same ‘surge’ might be harmful to other electrical devices and is one (of many) reason for no laser printer on that output. ‘Dirty’ electricity is why APC and others recommend not putting a power strip protector on that UPS output. They would rather not admit why – only say to not do it. Best power strip is one for about $4 with a necessary 15 amp circuit breaker and no protector components. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed Low End Mac's G3-5 List, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
