Suppose in a section of a circuit we encounter a combination of two resistors as in Fig. 17.4:
Figure
17.4: Two resistors in series |
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These resistors are said to be in series, and as indicated, it is possible to consider them as one single equivalent resistor R eq . To find this equivalent resistor, we exploit the fact from energy conservation that Vac = Vab + Vbc , which using Ohm's law (17.3) becomes
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IR
eq = IR1 + IR2
R
eq = R1 + R2. |
(7) |
This is readily extended to the case of multiple resistors R1,R2,...,RN in series:
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Req
= R1 + R2 +...+ RN. |
(8) |