4.3: Series and Parallel Capacitors
Capacitors, fundamental components in electronic circuits, can be connected in series and/or parallel configurations. Each configuration has different impacts on the overall behavior of the circuit.
First, consider capacitors connected in series to a battery. In this configuration, the plate connected to the battery's positive terminal develops a positive charge, while the plate attached to the negative terminal becomes negatively charged. An equal magnitude of charge is induced on the other plates, illustrating that the same current flows through each capacitor in a series connection.
Applying Kirchhoff's voltage law, which states that the total voltage around any closed loop in a circuit must equal zero, to the loop and substituting for the voltage across each capacitor yields an expression for the total voltage across the equivalent capacitor. In this case, the initial voltage across the equivalent capacitor equals the sum of the initial voltages across each capacitor. The reciprocal of the equivalent capacitance in a series connection is the sum of the reciprocals of the individual capacitances.
On the other hand, when capacitors are connected in parallel, the potential difference developed across each capacitor equals the battery voltage. This is because all the capacitors in a parallel configuration share the same voltage source.
By applying Kirchhoff's current law, which states that the total current entering a junction must equal the total current leaving it, and substituting the current for each capacitor, we can determine the total current flowing through the equivalent capacitor. In a parallel connection, the equivalent capacitance is simply the sum of the individual capacitances.
In conclusion, understanding how capacitors behave in series and parallel configurations is crucial in electronics. This knowledge allows engineers to manipulate the total capacitance of a circuit and, as a result, control the circuit's response to different signals. Whether in filtering applications, power supply smoothing, or signal coupling, capacitors and their configurations play a vital role.
