Electricity & Electronic Workbooks

(Martin Jones) #1

DC Network Theorems Unit 7 – Thevenin Circuits


To determine RTH, replace the source voltage with a short circuit, and calculate the total


resistance between terminals A and B of the network.


VTH and RTH make up the equivalent circuit. The original load is connected across terminals A


and B. VTH and RTH develop the same load voltage and load current as that of the original


network.


Two-source networks are thevenized in the same way. However, the superposition theorem can
be used to determine VTH.


NEW TERMS AND WORDS


Thevenin's theorem - a network can be represented by an equivalent VTH and a series RTH
circuit with respect to a selected pair of output terminals.
VTH - the Thevenin equivalent voltage of a network without a load.
RTH - the Thevenin equivalent resistance of a network without its source voltage.
Thevenizing - applying Thevenin's theorem to a network.


EQUIPMENT REQUIRED


F.A.C.E.T. base unit
DC NETWORK THEOREMS circuit board
Multimeter

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