How does a capacitor protect electronic devices from power surges?

📌 CONCEPT: A capacitor protects electronic devices from power surges by acting as a voltage regulator, allowing only a steady flow of current and preventing sudden spikes in voltage from reaching the device.

📐 RULE / FORMULA: The key principle behind this is the concept of capacitance, which is given by the formula C = Q / V, where C is the capacitance, Q is the charge stored, and V is the voltage across the capacitor.

💡 WORKED EXAMPLE: Suppose a capacitor with a capacitance of 10 μF is connected in series with a small electronic device that draws a steady current of 1 mA from a power source with a steady voltage of 5 V. If the power source surges to 10 V for a brief moment, the capacitor will store a charge of 10 μC and reduce the impact of the surge on the device, preventing damage from the sudden voltage increase.

⚠️ COMMON MISTAKE: Students often confuse the role of a capacitor as a voltage regulator with its role as a current regulator, failing to understand how capacitance affects the flow of voltage and current in a circuit.