Monophasic: Give one big dose of electricity which makes a single pass out one pad and to the other. Frequently ususes up to 360 joules.
Biphasic: MUCH BETTER TECHNOLOGY. Uses a lower dose of electricity which exits one pad goes the other and then comes back again. This requires lower engergy because the first pass lowers impedence. For asyncronous defibrilation uses up to 200 joules. typically 120 J, 160 J, or 200 J.
Hope this helps. You can also visit
www.zoll.com as I beleive they have information about both.
Sweetooth