The candidates were expected to connect the circuit as shown, measure and record the voltage(V) and current (mA), evaluate Ib and , plot a graph of IC (mA) against Ib(mA), determine and comment on the slope.
The expected answers were:
(c)
V1(V) |
IC(mA) |
Ib = |
|
1 |
5.407 |
30 |
180.00 |
3 |
5.413 |
230 |
23.53 |
5 |
5.421 |
430 |
12.61 |
7 |
5.426 |
630 |
8.61 |
9 |
5.428 |
830 |
6.54 |
- Average value of the d.c. current gain (Ib) = 430
(k) Slope of the graph = 26.6
(l) The average value of correct gain from the graph is about the same
value as the calculated
As reported by the Chief Examiner, the readings obtained by many of the candidates that answered this question showed that they did not have adequate knowledge on how to solder and to adjust meter settings to correspond to indicated values of measured quantities.