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Old 23rd December 2005, 17:34   #9 (permalink)
amit1101
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Join Date: Dec 2005
Location: faridabad
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Default I*i*r

Quote:
Originally Posted by navin
amit you are gonna hurt yourself. :-)

P is also = I*I*R. that is where typical amps trip up. current capacity.

Sam, my home brew 200W/ch 8 ohms home amp dumped over 500W in bridged mode into 8 ohms. Then again it has a 1200VA trany and 120,000uf of filter caps. The fact is I use about 10W of this 30kg beast. the rest is for show!
hello navin
here is the derivation in i square r format
suppose u have a normal amp , its a push pull amp and operates at +/- V rms volts
impedance of u r speaker be R ohms
during positive cycle the currrent through speaker is +V/R rms
during negative cycle the currrent through speaker is -V/R rms
total power is I*I*R where I= V/R rms
V*V/R watts ...........................................(1)

now u make an H bridge
since the voltage across speaker is now doubled the current will aslo double
bcoz V=I*R
thus in bridge
current during positive cycle is +2V/R
current during negative cycle is -2V/R
now power by I*I*R
(2V)(2v)/R
4*V*V/R watts ...........................................(2)

now the power in equation 2(bridge) is 4 times that of equation 1(normal)

amit
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