Three different timing circuits are built using ideal components and a 12 V battery
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Three different timing circuits are built using ideal components and a 12 V battery.
• Circuit A: A single 1.0 kΩ resistor in series with a 2.2 μF capacitor.
• Circuit B: Two 1.0 kΩ resistors connected in parallel; that parallel combination is in series with one 4.7 μF capacitor.
• Circuit C: A single 2.2 kΩ resistor in series with two 4.7 μF capacitors that are connected in parallel.
Each capacitor is initially uncharged when its circuit is connected to the battery.
(a) For each circuit, calculate the equivalent resistance.
(b) For each circuit, determine the equivalent capacitance.
(c) Compute the numerical value of the time constant τ for each circuit. Express your answers in milliseconds.
(d) Rank the circuits according to their time constants from greatest to least. State explicitly which capacitor will reach approximately 63 percent of its final charge in the shortest time and explain your reasoning.