Physics 9702 · AS & A Level · Rectification and smoothing

Rectification and smoothing — practice question

Figure 6.1 shows a bridge rectifier built from four ideal diodes A, B, C and D arranged as drawn. An alternating supply is connected across terminals X and Y.
(a(i))[1]

On Fig. 6.1, add the positive $(+)$ label for the load resistor $R$.

(a(ii))[1]

State which diodes are conducting when terminal $Y$ of the supply is positive. diode ................. and diode .................

(b)

Fig. 6.2 shows how the potential difference $V$ across the load resistor $R$ varies with time $t$.

(b(i))[3]

Use Fig. 6.2 to calculate the mean power dissipated in resistor $R$. The load resistor $R$ has resistance $2700\,\Omega$.

(b(ii))[1]

On Fig. 6.1, draw the symbol for a capacitor so that it is connected to increase the mean power dissipated in the resistor $R$.

(c)[2]

The capacitor from b(ii) is now taken out of the circuit. Diode A in Fig. 6.1 no longer works, so its resistance is infinite. On Fig. 6.2, sketch how the potential difference across resistor $R$ now varies with time $t$.

(i)[3]

Use Fig. 6.2 to calculate the mean power dissipated in resistor $R$.

(ii)[1]

On Fig. 6.1, draw the symbol for a capacitor so that the mean power dissipated in the resistor $R$ increases.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Positive indicated at the top of the resistor

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