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EXPERIMENT 6
Diode Characteristic and Application
PART A
Forward-bias Diode Characteristics
Silicon Diode (D1N4002)
Germanium Diode (1N34A)
1.
Construct the circuit as is shown in Fig. 6.1 using a Si
diode.
A
B
C
D
2.
3.
4.
By varying the DC Supply voltage, set the diode voltage VD = 0 V and
measure diode current ID and record the result in Table 6.1
Now, set the diode voltage VD = 0.1V. Measure the corresponding
diode current ID and record the result in Table 6.1
Repeat step 2 for the remaining settings of VD shown in the Table 6.1.
Table 6.1
VD (V)
ID (A)
0
0
0.1
0
0.2
0
0.3
5.45 A
0.4
40 A
0.5
0.29 mA
0.6
1.7 mA
0.65
4.35 mA
0.7
9.21 mA
5.
6.
Replace the Si diode by a Ge diode and complete Table 6.2.
Plot ID versus VD characteristics curves on a graph paper for
both silicon and germanium diodes.
Table 6.2
VD (V)
ID
0 0.1
0 0
0.2
81 A
0.3
1.175 mA
0.4
0.43
6.92 mA 9.47 mA
0.6
0.7
0.75
Conclusion: You should notice that the turn on voltage
for Ge diode is smaller than the silicon diode, which makes
it more efficient.
PART B
Half Wave Rectification
1.
Construct the circuit of Fig. 6.2. Set the supply to 9 V p-p
sinusoidal wave with the frequency of 2 kHz. Put the
oscilloscope probes at function generator and sketch the
input waveform obtained.
2.
Put the oscilloscope probes across the resistor and
sketch the output waveform obtained. Measure and
record the DC level of the output voltage using the
DMM.
+Vsine
+
OSCILLOSCOPE
A
+
B
OSCILLOSCOPE
D1N4002
2.2 k
-
-
GND
3.
Reverse the diode of circuit of Fig. 6.2. Sketch the
output waveform across the resistor. Measure and
record the DC level of the output voltage.