Question 4
- List:
- three stages of a stabilized d.c. power supply unit;
- two types of multivibrators.
- Fig. 3 is the diagram of an RL circuit at resonance.
Calculate the:
- Voltage across the coil;
- Current flowing in the circuit;
- Inductance of the coil.
Observation
The expected responses were:
(a) (i) Stages of a stabilized d.c. power supply unit
- Transformer/transformation stage
- Rectifier/rectification stage
- Filter/filtering stage/smoothening stage
- Regulator/regulating stage/stabilizer
- Voltage divider/selector
(ii) Types of multivibrator
- Astable/free running multivibrator
- Mono stable/one shot multivibrator
- Bistable/flip-flop multivibrator
Question 4 required candidates to state the stages in a d.c. power supply unit and types of multivibrators. It also included a circuit that required analysis. The Chief Examiner reported that while majority of the candidates that attempted the task in 4(a) responded quite well, only a few of them responded well to the task in 4(b).