Physics 9702 · AS & A Level · Rectification and smoothing
Rectification and smoothing — practice question
Fig. 8.1 illustrates a circuit that converts an alternating input voltage into a rectified output. The input voltage $V_{IN}$ is sinusoidal, and the rectified output voltage $V_{OUT}$ is across resistor $R$. In Fig. 8.2, the variation of $V_{IN}$ with time $t$ has amplitude $V_0$ and period $T$. The root-mean-square (r.m.s.) value of $V_{IN}$ is $6.0\,\text{V}$.
(a(i))[1]
State the form of rectification produced by the circuit in Fig. 8.1.
(a(ii))[1]
Calculate the value of $V_0$.
(b(i))[2]
Resistor $R$ has resistance $45\,\Omega$. Assume that there is no p.d. across the diode when it is conducting. Determine the peak power $P_0$ in the resistor.
(b(ii))[3]
On Fig. 8.3, sketch how the power $P$ in the resistor varies with $t$ for $t = 0$ to $t = 2T$.
(b(iii))[2]
Use the result in (b)(ii) to explain why the mean power in the resistor is $\frac{1}{4} P_0$.
(b(iv))[1]
Use the information in (b)(iii) to find the r.m.s. value of $V_{OUT}$.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “half-wave rectification is produced” …