Capacitors in DC Circuits

Some representative dielectric constants are 1.0 for air, 5 for mica, 6 for glass, and 7500 for ceramic. 

Since the current is defined as the change rate of the charge, by differentiating Equation 2.18 we can obtain 

Since the current to all the elements in a series circuit is the same, the accumulation of charge in every capacitor must be the same. Thus, 

the equivalent capacitance of n capacitors in series, Cs, is determined by 

In other words, the total capacitance of capacitors in series is equal to the reciprocal of the sum of the reciprocals of the individual capacitances. 

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