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Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Chapter 3
저항 회로망 해석
김소담 김수진 김영은 김현희 이지혜
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
Step 1
Select a reference node.
Step 2
Identify all node voltages.
Identify all element currents.
Step 3
Write (N-1) KCL equations.
Step 4
Express element current in terms of node
voltages.
Step 5
Substitute and rearrange.
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
Step 4
Step 3
Step 5
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis 정리
→ (N-1) node voltages
N개의 node
→ (N-1) KCL equations
→ AX = B , 해 = x
A: 회로에 대한 정보 (저항값)
B: source (is)
X: Node Voltage
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
* 전압원의 처리 방법 (전압원이 불편한 경우)
1) Source Transformation
Is =
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Rs
Vs
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
* 전압원의 처리 방법 (전압원이 불편한 경우)
1) Source Transformation
Ex)
Step 3
Step 4
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
* 전압원의 처리 방법 (전압원이 불편한 경우)
2) Reference node selection
Ex)
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Node Voltage Analysis
* 전압원의 처리 방법 (전압원이 불편한 경우)
3) Super Node
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Mesh Current Analysis
Mesh : a loop that does not enclose an element
:mesh
Step 1
Identity a mesh current for every mesh and a voltage across
every element
Step 2
Write KVL constraints around all meshes
Step 3
Express element Voltage in terms of mesh current
Step 4
Substitute and rearrange and solve
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Mesh Current Analysis Example
Example
V1
V2
①
V0
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iA
iB
V4
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
11
학생 작성 강의록
Ex)
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Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Mesh Current Analysis 요령
①
②
A current source in only one mesh
→ mesh current = source current
③
A current source in two meshes or
A current source with series resistor
→ Super mesh
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Mesh Current Analysis 요령
Ex1)
8V= 4kΩ X 2mA
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Mesh Current Analysis 요령
Ex2)
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Linearity - 선형성
- Input : Signal produced by independent source
- Output : any other designated signal
ex) 전압원 전류원
ex) 전압, 전류
* Linear Circuit (선형회로) 은 아래의 2가지 조건을 만족시켜야 한다.
① Homogenity (Proportionality) :
② Additivity (Superposition) :
f(kx) = k f(x)
f(x1+x2) = f(x1)+f(x2)
* R(저항) L(인덕터) C(커패시터) 만을 포함하는 회로는 선형회로
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Bridge circuit Example
V2
V1
VO
V3
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V4
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학생 작성 강의록
Dept. of Biomed. Eng.
Case 1
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BME207: Basic Electronic Circuits
is=0 일때
Case 2
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Kyung Hee Univ.
Vs=0 일때
학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Principle of Superposition(중첩의 원리)
선형회로에서만 사용가능!!
압력이 여러 개일 때 출력은 각각 입력했을 때의 결과값의 합과 동일
Turn off all independent
sources(input)
Find output for each
input only
Add all outputs
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
ex)
Vs= Vo1 + Vo2 + Vo3
=1/3(Vs1+Vs2+Vs3)
평균값
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
21
학생 작성 강의록
ex)
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Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
ex)
끊어져서 i=0이 되므로
같은 노드가 됨!
저항이 없는 것이라고
생각~
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Thevenin and Norton Equivalent Circuit
RT=RN
VT=IN*RT
방법2
방법1
VT=Voc :개방전압
iN =isc :단락전류
RT=RN=VT/VN
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VT=Voc
RT : 모든 전원을 제거한 후의
등가저항
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
ex)
부
하 Vo
Thevenin
선형회로
방법1
VT=VOC=
R2
VS
R1+R3
RT=R3+(R1//R2)
R1R2
=R3+ R1+R2
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
방법2
Isc
=R3+
R1R2
R1+R2
R2
R1+R3
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Loading Effect(부하효과)
부하저항에 따라 V, I, P 가 변함
최대출력전압 VLmax=VT=Voc
RT
VT
최소출력전류=0 (RL=∞)
Vo
최대출력전압 VLmin=0=Vsc
전력
=0
최소출력전류=VT/RT (RL=0)
RL
VL
IL
PL
0
0
VT/RT
0
…
…
…
∞
VT
0
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커졌다 작아짐
0
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
PL
VL
VT
VT
RT
2
(VT)
4RT
RL
RT=RL 일 때 P최댓값
PLMAX
VL(RL=RT) = 1/2VT
iT (RL=RT) = VT/2RL
PL(RL=RT) = (VT)^2/4RL
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
Nonlinear Load
iL
RT
VT
iL
VL
load
VT
RT
Load line
(부하선)
VL
VT
무엇이 연결되든 간에
위의 선(부하선)을
만족해야한다
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학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
iL
iL
RL VL
1
:Slope iL
RL
:Ohm’s
Law
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VL
부하의 소자에 따라 결정
<선형부하의 i-V특성 곡선>
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VL
Element constraint와
Load line 그래프의 교점
학생 작성 강의록
Dept. of Biomed. Eng.
BME207: Basic Electronic Circuits
Kyung Hee Univ.
3장 끝
Thank you!
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학생 작성 강의록