Question 2
AIM: To determine the forward voltage drop of a diode.
- Connect the circuit as shown in Figure 2.
- Ask the supervisor to check the circuit connection.
- You are provided with Table 2.
- Set the output voltage, V1(V) of the variace to 4 V.
- Close switch S.
- Read and record in Table 2, the value of Voltmeter V2.
- Open switch S
- Increase the variace output V1 in steps of 2 V
- Repeat steps (e) to (h) for up to 12 V as shown in Table 2.
- Complete Table 2.
- Plot a graph of current I (mA) on the vertical axis against change in voltage ∆V(V) on the horizontal axis.
- Determine the slope of the graph
- From the graph, determine the forward voltage drop ∆V(V) of the diode for a supply voltage of 9 V.
Observation
The expected answers were:
TABLE 2
- Circuit connection
- Correct calculation of Vx
- Correct calculation of I
- Correct calculation of ∆V
- Correct readings of V2
- Correct axes
- Reasonable scale
- Plotting of points
- Line of best fit
- Determination of slope
GRAPH AND CALCULATIONS
This question is to determine the forward voltage drop of a diode. The strengths and weaknesses exhibited by candidates in question 1 are similar to the ones here as well in relation to understanding what is expected of them and inability to take accurate readings.