University of Technical Education Faculty of Electrical & Electronic Engineering
Lecture: DIGITAL SYSTEMS Chapter 10: O s c i l l a t o r a n d Ti m e r
Nguyen Thanh Hai, PhD 1
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates 10.2 Monostable Circuit Using Logic Gates 10.3 Oscillator Using IC 555 10.4 Monostable Circuit Using IC555
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates VCC B
R 3
Q
1
R2
C1
R1
C2 A
2
Q
VCC Oscillator using NAND gate
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates VCC
VCC B
R
B
Q
1
Q
1
R2
C1
R2
C1
R1
C2
R1
C2
A VCC
2
Q
R
A
Q
2
VCC
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates Q
t 0
T1
R1
R2 R
T2
C 1
Q
C 2
C
t
0
T T 1
T 2
2( R R3 )C . ln 2 1,4( R R3 )C 5
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer R
10.1 Oscillator Using Logic Gates
VCC
Oscillator with inverse gate of Schmitt trigger
A C
R
R
VCC
VCC
A C
Q
A Q
C
Q 6
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates
Q
t 0
T1 T 2T 1
T2
2T 2
RC . ln 2 RC
V OH
V IL IL
V OH
V IH IH
Oscillator Oscilla tor with inverse gate of Schmitt trigger 7
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates
8
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.1 Oscillator Using Logic Gates
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.2 Monostable Cicuit Using Logic Gates
VCC
VCC V
X
Y
1
1 0
C
Z
2
Monostable circuit using NAND gate
R
X
t 0
T
t Z
. ln 2 0.7 RC RC
RC RC
t 0 T
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.2 Monostable Cicuit Using Logic Gates
Monostable circuit using NAND gate
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.2 Monostable Cicuit Using Logic Gates VCC X
VCC V
Y
1 C
1 0
Z
2 R
Monostable circuit using NOr gate
X
VCC
t
T
RC . ln 2 0.7 RC
RC RC
0
t Z
t 0
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.2 Monostable Cicuit Using Logic Gates
Monostable circuit using NOr gate
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.3 Oscillator Using IC555
Structure of IC 555
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.3 Oscillator Using IC555
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.3 Oscillator Using IC555
T 1
N
ln 2 0,7C R1 R2
T T 1 T 2
T 2
X
0,7C R1 R2 0,7CR2
ln 2 0,7CR2
0,7 R1 2 R2 C 16
University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.4 Monostable Using IC555
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer 10.4 Monostable Using IC555
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University of Technical Education Faculty of Electrical & Electronic Engineering
Oscillator and Timer
-Take a look Examples from pages - Answer Review questions at questions at page - Homework
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University of Technical Education Faculty of Electrical & Electronic Engineering
