The candidates were expected to connect the circuit as shown above, obtain the voltmeters readings, plot a graph of the output voltage against the input voltage and from the graph explain the stabilization effect of the Zener diode
The expected answers were:
Table 1
Vin(V) |
0 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
Vout(V) |
0 |
2 |
3 |
4 |
5 |
6 |
6.3 |
6.3 |
6.3 |
6.3 |
- As long as the input voltage is lower than the Zener voltage of the Zener diode, the Zener diode will not influence the output voltage.
As soon as the input voltage becomes higher than the Zener voltage of the Zener diode, the voltage at the Zener diode or the input voltage will remain constant.
The candidates understood the task, connected the circuit and obtained readings but failed in the theory of diodes and Zener diode characteristics.