Question 3
AIM: To determine the output characteristics of a transistor in common emitter configuration.

(a)  Connect the circuit as shown in Fig. 3.
(b)  Ask the supervisor to check the circuit connection.
(c)  Copy Table 3 into your answer booklet.

Table 2

(d)  Close switches S1 and S2.
(e)  Set the base emitter voltage (V1) to 0.7 V.
(f)  Set the voltage (V2) to 0.4 V, measure and record the corresponding value of IC in       Table 3.
(g)  Repeat step  (f) for other values of VCE (V) in Table 3.
(h)  Open switches S1 and S2.
(i)   Plot a graph of IC ( on the vertical axis against VCE (V) on the horizontal axis.
(j)   Determine the slope of the graph.
(k)  Comment briefly on the slope of the graph.
The candidates were expected to connect the circuit as shown in Fig. 3, measure and record in Table 3 the expected IC (mA) readings. They were also required to plot a graph of IC ( against VCE (V), calculate the slope and comment briefly on it.
The expected answers were:
(c)                                                        Table 3
           

VCE()	IC(mA)
0.4	0.813 – 2.89
0.8	3.00 - 5.481
1.0	3.01 - 8.722
2.0	3.10 - 15.363
4.0	3.25 - 16.453
6.0	3.51 - 18.544