Post on 30-Jun-2015
Penguat Emiter Sekutu
RC
RE
R1
R2
+VCC
RS
0V
VB
RL
0V
Rangkaian Ekivalen
RS
RL
RC
RE
R1
R2
+VCC
RC
RE
R1
R2
+VCC
Rangkaian Ekivalen DC
RCR1 R2
RS
RL
Rangkaian Ekivalen AC
Resistansi Emiter AC
re’ = Vbe / Ie atau
re’ = vbe / ie
Harga pendekatan : re’ = 25mV / Ie
Beta AC = Ic / Ib
= ic / ib
Penguatan Teganganie = vin / re’
ic ≈ ie
vout ≈ -ic.Rc
≈ - vin .RC / re’
A = vout / vin ≈ - RC / re’
Impedansi Masukan
RCR1 R2
RS
re’vini1 i2
ib
zin zin(basis)
RCR1 R2 b.re’vini1 i2
ib
zin zin(basis)
ic
zin = zin(basis) // R1 // R2zin(basis) = b.re’
Impedansi Keluaran
RCR1 R2 b.re’vini1 i2
ib
zin zin(basis)
ic
zout
ic
zout ≈ RC
Contoh 7-1
3K6
1K
10K
2K2
+10V
vin
VB = 10V.2K2 / (10K + 2K2) =1,8VVE = VB – VBE = 1,8V – 0,7V = 1,1VIE = VE / RE
= 1,1V / 1K =1,1mAVC = VCC – IC.RC
= 10V – 1,1mA.3K6 = 6,04V
re’ = 25mV / 1,1mA = 22,7WA = RC / re’
= -159