Capacitor discharge time - how to calculate with examples

The video tutorial explains the behavior of capacitors in circuits, focusing on how they charge and discharge over time. It introduces the concept of the time constant, which is the product of resistance and capacitance, and describes how this affects the rate of voltage change in a capacitor. The tutorial provides examples with different resistor and capacitor values, illustrating how these components influence the time taken for a capacitor to charge or discharge. The video also explains that the voltage across a capacitor follows an exponential curve, never reaching 100% but approaching it closely over several time constants.

What is the voltage percentage of a capacitor at the first time constant during discharge?

• 36.8%

• 63.2%

• 50%

• 25%

How long does it take for a capacitor to charge to nearly full voltage in a series circuit with a 10K ohm resistor and a 100 microfarad capacitor?

• 0.5 seconds

• 10 seconds

• 5 seconds

• 1 second

What is the formula to calculate the time constant in a circuit?

• Resistance in ohms multiplied by capacitance in farads

• Voltage divided by current

• Resistance in ohms divided by capacitance in farads

• Capacitance in farads divided by resistance in ohms

If the resistor value increases, what happens to the time taken for a capacitor to charge?

• Time becomes zero

• Time increases

• Time remains the same

• Time decreases

At what voltage percentage does a capacitor reach after one time constant during charging?

• 63.2%

• 100%

• 36.8%

• 95%

What happens to the current in the circuit as the capacitor reaches full voltage?

• Current increases

• Current stops flowing

• Current remains constant

• Current decreases

How does the brightness of a lamp change as a capacitor charges in a circuit?

• It becomes brighter

• It becomes dimmer

• It remains constant

• It flickers