Physics 9702 · AS & A Level · Rectification and smoothing

Rectification and smoothing — practice question

A section of an electric circuit is shown in Fig. 5.1. This circuit is used to obtain half-wave rectification of an alternating voltage with potential difference (p.d.) $V_{\text{IN}}$. The output p.d. across the $14\,\text{k}\Omega$ resistor is $V_{\text{OUT}}$.
(a(i))[1]

One part is missing from the circuit in Fig. 5.1. Finish the circuit diagram in Fig. 5.1 by inserting the circuit symbol for the missing component in the correct connection.

(a(ii))[1]

A capacitor $C$ is included in the circuit of Fig. 5.1. State the effect on $V_{\text{OUT}}$ when the capacitor is added to the circuit.

(b(i))[1]

Determine the frequency of $V_{\text{IN}}$.

(b(ii))[2]

Show that the time constant $\tau$ for the discharge of the capacitor through the resistor is $0.038\,\text{s}$.

(b(iii))[2]

Calculate the capacitance of $C$. Give a unit with your answer.

(c)[2]

The circuit of Fig. 5.1 is altered so that it gives full-wave rectification of an input voltage. Suggest, with a reason, how $V_{\text{OUT}}$ now changes with time when $V_{\text{IN}}$ is as shown in Fig. 5.2.

(c(i))[1]

Determine the frequency of $V_{\text{IN}}$.

(c(ii))[2]

Show that the time constant $\tau$ for the discharge of the capacitor through the resistor is $0.038\,\text{s}$.

(c(iii))[2]

Calculate the capacitance of $C$. Give a unit with your answer.

(d)[2]

The circuit of Fig. 5.1 is altered so that it gives full-wave rectification of an input voltage. Suggest, with a reason, how $V_{\text{OUT}}$ now changes with time when $V_{\text{IN}}$ is as shown in Fig. 5.2.

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: correct diode symbol connected in series in circuit

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