# Worksheet: Uses of Capacitors

In this worksheet, we will practice describing how capacitors can be used in smoothing rectified current sources and in timing circuits.

Q1:

The diagram shows four circuits containing capacitors and a resistor connected to a rectified voltage source. Which circuit acts as a smoothing circuit for the potential difference measured across the resistor? • A(a)
• B(d)
• C(b)
• D(c)

Q2:

The diagram shows a potential divider containing a resistor and a capacitor. Initially, no charge is stored in the capacitor. What is the potential difference across the capacitor immediately after the switch is closed?

• A0 V
• B10 V
• C15 V
• D1.5 V
• E5 V

What is the potential difference across the resistor immediately after the switch is closed?

• A10 V
• B0 V
• C15 V
• D5 V
• E1.5 V

What is the output voltage immediately after the switch is closed?

• A5 V
• B10 V
• C15 V
• D0 V
• E1.5 V

The capacitor takes 30 s to fully charge. What is the output voltage after 30 s?

• A15 V
• B1.5 V
• C5 V
• D10 V
• E0 V

Q3:

Diagram (a) shows a capacitor and a resistor connected in parallel across a rectified voltage source. The voltmeter measures the potential difference across the resistor over time. Diagram (b) shows the graph of the input voltage against time. Which of the following graphs shows the potential difference against time as measured by the voltmeter?

• A • B • C • D Which of the following is the correct name for this type of circuit?

• AA timing circuit
• BA sensing circuit
• CA bridge circuit
• DA half-wave rectification circuit
• EA smoothing circuit