Capacitors in series Like other electrical elements, capacitors serve no purpose when used alone in a circuit. They are connected to other elements in a circuit in one of two ways: either in series or in parallel. In some cases it is useful to connect several capacitors in series in order to make a functional block: Analysis When this block is connected to a voltage source, each capacitor in the block stores an equal amount of charge, which means that the total amount of charge is evenly distributed across all of the capacitors, regardless of their capacitance. The amount of charge stored at each capacitor equals: where Qtotal is the total amount of charge in the complete block, and Q1 to Qn are charges at each individual capacitor. In order to explain why the charges at every capacitor are mutually equal, and equal to the total amount of charge stored in the complete series connection block, let us assume that all capacitors were uncharged at one point in time. When voltage is first applied across the block, the same current flows through all the capacitors and as a result, charge shift occurs. Electrons are carried from one plate of each capacitor to the other, which means that the charge stored by a plate of any of the capacitors must have come from the adjacent capacitor’s plate. This means that charge carriers (electrons) have simply shifted through all the capacitors, which is the reason that the charges at each capacitor are equal. That being said, it must be noted that the voltages across each capacitor are not equal, and are calculated for each capacitor by using the known formula: where Qn is the amount of charge on every capacitor in the series connection, Cn is the capacitance of the...
[Read more]
Tag: