Equation 18-11 tells us that by combining resistors in series, we create a circuit with a higher equivalent resistance than that of any of the individual resistors. A special case is when we put two identical resistors \(R\) in series. The equivalent resistance is
\(R_{\mathrm{equiv}} = R + R = 2R\)
The equivalent resistance of two identical resistors in series is twice that of each indi vidual resistor.