Capacitors:
Capacitors store electrical energy (electric charge on metal plates). The current through a capacitor is proportional to the rate of change of the voltage across the capacitor.
Schematic symbol(s)
Capacitance is the proportionality between charge and potential (voltage).
Capacitance is also the dynamic relationship between the current flowing through the capacitor (rate of change of charge) and the rate of change of the voltage.
Recall :
Units: The unit of capacitance is the farad.
(A farad is a coulomb per volt and an ampere-second per volt.)
Practical information:
Capacitance: The farad is a large unit. Typical capacitance values are measured in microfarads (μF = 10−6 F), nanofarads (nF = 10−9 F), and picofarads (pF = 10−12 F).
Voltage (working voltage): Capacitors are rated for the maximum working voltage. Voltages higher than this may damage the capacitor irreversibly.
Polarization: Some types of capacitors are polarized. The capacitor needs to be connected to the circuit in the correct polarity. Reversing the polarity can damage the capacitor. Often the capacitance is dramatically different if the polarity is incorrect; some even look more like resistors.
Types of dielectric: The type of dielectric (insulator) between the plates determines the detailed electrical characteristics of the capacitor, such as leakage, physical size, and high frequency performance. In this class we will not be concerned with these details. It is however necessary to understand that these details are responsible for the wide variety of shapes, sizes, colours, and types of capacitors.
Capacitors in parallel: The equivalent capacitance of capacitors in parallel is the sum of the capacitances of all of the capacitors.
Capacitors in parallel:
Capacitors in series: The equivalent capacitance of capacitors in series is the reciprocal of the sum of the reciprocals of the capacitances of all of the series capacitors.
Capacitors in series:
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