Download EKT104 Analog electronic circuits

[EKT104 ANALOG ELECTRONIC CIRCUITS ]
Sem. 2 2014/2015
NOTES
Common-Emitter Amplifier Circuit
Small signal resistance
r 
ro 
 VT
I CQ
VA
I CQ
Hybrid-π Model Equivalent Circuit
Input resistance
Transconductance Parameter
Ri  RB // r  R1 // R2 // r
gm 
Output resistance
Ro  ro // RC
Output Voltage
vo  I o Ro  I b (ro // RC )
I CQ
VT
Small Signal Voltage gain
Av 
 R1 R2 r
Vo

  gm 

Vs
 R1 R2 r  RS
Input Voltage
vi 
RB // r
 vs
RB // r  Rs
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School of Computer and Communication Engineering, UniMAP
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r R 
 o C
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[EKT104 ANALOG ELECTRONIC CIRCUITS ]
Sem. 2 2014/2015
Tutorial 1 (Common Emitter Amplifier)
(a)
Determine the small signal parameters gm,rπ and ro of a transistor with parameters
𝛽=180 and VA=150V for bias currents of (i) ICQ=0.5mA and (ii) ICQ=2mA.
(b)
Given that a transistor parameters are 𝛽=125 and VA=200V. A value of gm=95mA/V
is desired. Determine the required collector current and then find rπ and ro.
(c)
C-E amplifier; Given R1 = 50kΩ, R2 = 50kΩ, RC = 6kΩ, RS = 0.5kΩ, VCC = 12V,  =
100, VBE(on) = 0.7V, VA=100V, VT = 0.026. Construct the Hyrid-π equivalent circuit
and then determine the following;
(i)
The quiescent values; ICQ , VCEQ.
(ii)
Plot the Q-point on the dc load lines
(iii)
Transconductance parameter, gm
(iv)
The resistances values; rπ and ro
(v)
The small signal voltage gain, Av (consider early effect)
(d)
C-E amplifier: Given  = 150, VCC = 12V, VBE = 0.7V, RC = 5k, RB = 20k, and VBB =
1.2V. Calculate the collector-emitter voltage at q-point and small-signal voltage gain.
V
CC
R
C
v
R
O
B
v
s
V
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BB
School of Computer and Communication Engineering, UniMAP