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ME3000 Analog Electronics
Lab 6 - 4/19
2.
DC Biasing
1. Locate the Class A Tuned Amplifier section on the ME3000-M1 training kit.
2. Disconnect all the jumpers located in the Class A Tuned Amplifier section.
3. Construct an RF Class A amplifier circuit shown in Figure 4 by connecting jumpers to J28 and
J29.
4. Connect the power supply to the training kit using the 4-way power supply cable. Set the
power supply voltage to +15 V. Turn on the power supply. Refer to Appendix for details.
5. Use the multimeter to measure V
CC
applied to the transistor (between terminals TP4 and
GND). Calculate the voltage at the transistor base using the resistive voltage divider formula,
CC
B
V
R
R
R
V
17
16
17
, where R17 = 4.7k and R16 = 10k. Then, calculate the voltage at the
transistor emitter, V
E
using V
E
= V
B
– 0.7.
6. Measure V
C
(at TP2 and GND), V
B
(at TP3 and GND), and V
E
(at TP5 and GND) on the
transistor C, B, E pins.
7. Verify that V
B
– V
E
≈ 0.7 V.
8. Check if the calculated V
B
and V
E
values agree with the measured values.
9. Estimate I
C
using
E
E
E
C
R
V
I
I
, where R
E
= R18 = 150
.
10. Determine the transconductance, gm of the transistor at T = 25
using
26
)
(
mA
I
g
C
m
.
Vcc
Q3
C7
C8
L1
R17
R18
C6
R16
Input
Output
C10
R19
Figure 4 – Schematic Diagram of DC Biasing on an RF Class A Amplifier
