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CAIE A-Level Physics A2 21.2 Rectification and Smoothing Questions

Practise explaining half-wave and bridge rectification, analysing capacitor smoothing and relating capacitance, load resistance and ripple.

Syllabus
2028–2030
Course
Physics 9702
Level
A2

Exam points

  • distinguish and explain half-wave and bridge full-wave rectification
  • analyse capacitor smoothing and the effects of capacitance, load resistance and ripple

Covered syllabus points

21.2.1—Distinguish graphically between half-wave and full-wave rectification21.2.2—The use of a single diode for the half-wave rectification of an alternating21.2.3—The use of four diodes (bridge rectifier) for the full-wave rectification of21.2.4—The effect of a single capacitor in smoothing

Question 1

[Maximum number: 2]

Four diodes are used in a bridge rectifier circuit to produce rectification of a sinusoidal a.c. input voltage VIN V_{\text {IN }}.
Fig. 7.1 shows part of the circuit, but three of the diodes are missing.

Fig. 7.1

Fig. 7.1

The p.d. across the load resistor R is the output p.d. VOUT V_{\text {OUT }} of the bridge rectifier.

VIN V_{\text {IN }} has amplitude V0V_{0} and period T. Fig. 7.2 shows the variation with time t of VIN V_{\text {IN }}.

Fig. 7.2

Fig. 7.2

The power dissipated in the resistor is P.

On Fig. 7.4, sketch the variation of P with t between t=0 and t=2.0 T.

Fig. 7.4

Fig. 7.4

Question 2

[Maximum number: 3]

Fig. 8.1 shows a circuit that produces rectification of an alternating input voltage.

Fig. 8.1

Fig. 8.1

The input voltage VIN V_{\text {IN }} is sinusoidal. The rectified output voltage VOUT V_{\text {OUT }} is applied across resistor R.
The variation of VIN V_{\text {IN }} with time t has amplitude V0V_{0} and period T, as shown in Fig. 8.2.

Fig. 8.2

Fig. 8.2

The root-mean-square (r.m.s.) value of VIN V_{\text {IN }} is 6.0 V .

Resistor R has resistance 45Ω45 \Omega.

Assume that there is no p.d. across the diode when it is conducting.

On Fig. 8.3, sketch the variation of the power P in the resistor with t between t=0 and t=2 T.

Fig. 8.3

Fig. 8.3

All question bank results loaded