Unformatted text preview: art of the power supplied to the load will be lost in the Thevenin resistance. iL VT
rL RT pL i r 2
LL VT2 rL RT 2 rL The power transfer between the source and the load will be dependent on the load resistance. The value of load resistance for which the load power will be maximum, dp L 0 . drL 2
2
dp L vT (rL RT ) 2 2vT rL (rL RT ) 0
drL
(rL RT ) 4
2
2
vT (rL RT ) 2 2vT rL (rL RT ) 0 rL RT This implies that the power transfer to the load will be maximum when the load resistance is equal to the Thevenin resistance. Energy efficiency PL
, i.e. the ratio power absorbed by the load to the power delivered by the Psource source. pL
p source 2
i L rL i L rL
VT
rL
rL VT i L
VT
rL RT VT rL RT It can be observed that the efficiency of the system is only 50% when the maximum power transfer occurs. Hence, maximum power transfer is not desirable for high power systems as considerable power would be wasted. For high power systems, the efficiency is vey important and hence, it is desirable to have minimum (zero would make an ideal source) internal r...
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This document was uploaded on 01/20/2014.
 Winter '14

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