I would like to learn more about large-scale UPS systems, particularly the battery strings used in traditional RBOC/Telco applications. These are the sort of beasts that use huge strings of 6V 220aH deep cycle batteries, or even large numbers of 2V 400aH batteries on very strong earthquake-resistant shelving wired up to create a 48V mega-battery. Can anyone point me to the most definitive reference materials on the subject?
posted by thewalrus on Dec 17, 2009 - 4 answers

Can you show me a photo beam sensor or a magnetic sensor that is close to the size of my pinky? [more inside]
posted by kaozity on Dec 3, 2007 - 8 answers

2 outlets & a ceiling light stopped working at the same time. None of the circuit breakers were flipped. What would cause this, and how can I troubleshoot it? [more inside]
posted by designbot on Aug 30, 2007 - 15 answers

Looking for resources that will teach me how to use capacitors, resistors, solar cells and other electrical components. [more inside]
posted by Alison on Jun 22, 2006 - 13 answers

The outlets in my new apartment are two pronged. I've been tearing the third prong off of power strips in order to plug them into the wall. Is this bad?
posted by tomharpel on Feb 13, 2005 - 18 answers