Capacitors PDF

CAPACITORS A capacitor is a two-terminal, electrical component. Along with resistors and inductors, they are one of the most fundamental passive components we use. What makes capacitors special is their ability to store energy; they're like a fully charged electric battery. Caps, as we...

CAPACITORS A capacitor is a two-terminal, electrical component. Along with resistors and inductors, they are one of the most fundamental passive components we use. What makes capacitors special is their ability to store energy; they're like a fully charged electric battery. Caps, as we usually refer to them, have all sorts of critical applications in circuits. Common applications include local energy storage, voltage spike suppression, and complex signal filtering. How Capacitor Works? A capacitor temporarily stores electrical energy through distributing charged particles on (generally two) plates to create a potential difference. CAPACITORS Not all capacitors are created equal. Each capacitor is built to have a specific amount of capacitance. The capacitance of a capacitor tells you how much charge it can store, more capacitance means more capacity to store charge. The standard unit of capacitance is called the farad, which is abbreviated F. CAPACITORS CAPACITANCE Factors that affect capacitance. 1. If we maintain constant spacing between the sheets and increase their mutual area, the capacitance goes up. 2. If we maintain constant spacing between the sheets and decrease their mutual area, the capacitance goes down. 3. If we maintain constant mutual area and move the sheets closer together, the capacitance goes up. 4. If we maintain constant mutual area and move the sheets farther apart, the capacitance goes down. Capacitance is also affected by the dielectric constant Capacitors in Series When we connect two or more capacitors in series, their values combine just as resistances combine in parallel In general, if we have several capacitors connected in series, we observe a net capacitance smaller than that of any of the individual components. As with resistances and inductances, we should always use the same size units when we calculate the net capacitance of any combination. Sample Problem Suppose that two capacitances, C 1 = 0.10 μF and C 2 = 0.050 μF, appear in series, as shown in the figure below. What is the net capacitance? Sample Problem: Imagine that we connect two capacitors with values of 0.0010 μF and 100pF in series. What’s the net capacitance? Capacitors in Parallel Capacitances in parallel add like resistances in series. The net capacitance equals the sum of the individual component values, as long as we use the same units all the way through our calculations. Suppose that we connect capacitors C1 , C2 , C3 , …, Cn in parallel. Sample Problem Imagine three capacitors connected in parallel, having values of C1=0.100μF, C2= 0.0100 μF, and C 3 = 0.00100 μF, as shown in Fig. below. What’s the net parallel capacitance?