Basic Circuit Concepts Circuit Analysis Overview Circuit ... · Basic Circuit Concepts Circuit...
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Basic Circuit Concepts
Circuit Analysis Overview
Circuit Variables: v(t), i(t), q(t), f(t)
Circuit Elements: Vs, Is, R, L, C, etc.
Basic Circuit Theorems: KCL and KVL
Simple Resistive Circuits
Node Analysis Method
Mesh Analysis Method
Equivalent Circuits: Thevenin and Norton Equivalent Circuits
Impedance Matching: Maximum Power Transfer
Electrical Engineering Design Model
電路分析的應用:模型分析
Circuit whichmeets designspecifications
Laboratorymeasurements
Refinement basedon analysis
Refinement basedon measurements
Physicalinsight
CircuitCircuitanalysisanalysis
Need
Design Specifications
Concept
CircuitModel
PhysicalPrototype
Circuit Variables
Voltage
Current
公 式定 義電路變數
the energy per unit charge created by the charge separation
the rate of charge flow
-v = dw/dq
-i = dq/dt
+
1 Coulomb = charge contained in 6.24 x 1018 electrons
e- = -1.6022 x 10–19 Coulomb (C)
Ideal Basic Circuit Element
Only two terminals
Cannot be divided into other elements
+v-
1
2
i
Described mathematically by current and/or voltage
負流向:電壓從負端流進。
Tips電壓降(voltage drop):電壓從第1點流向第2點,是由正到負。電壓升(voltage rise):電壓從第2點流向第1點,是由負到正。正流向:電壓從正端流進。
Power and Energy
AA
vidtdq
dqdw
dtdwp === ))((
If p > 0, power is delivered to the circuit inside the box.If p < 0, power is being extracted ( generated) from the circuit inside the box.
Tips
1
2
+
-V
p=V i
+
- 1
2V
p= -V i
1
2
+
-V
p= -V i
1
2+
-V
p=V i
i i
i i
CC
BB DD
Circuit Elements
Circuit Elements電路元件
Voltage電壓源 Current電 流源
Dependent Sources Dependent SourcesIndependent SourceIndependent Source 相依型 相依型獨立型獨立型
Independent Source: Active elements
v
i
vssupplydissipate
Tips
Depending on the direction of current, an independent voltage source can supply power or dissipate power.Depending on the polarity of its terminal voltage, an independent current source can supply power or dissipate power.
v
iis
supply
dissipate
i+-
vs
+
-Vis
項目 圖 示 象限說明
電流源
電壓源
Dependent Sources: Active elements
相依型電壓電流源:依據某個電路變數而變化的
電路變數 Voltage-controlled Current-controlled
圖 示
圖 示
公 式
公式
i+-
+-V
i +-
+-V
εv= µvx =αvxis
εv= ρix = βixis
A. B.
C. D.
Electric Capacitance
電容:儲存電荷的元件
電容符號
+
-
i
V C
C (t)
C(t)
iC(t)
+
-V CC(t)
iC(t)
+
-V CC(t)
Charge on capacitorCharge on capacitor
C = q(t) = CvC(t)
A. B. C.
Current of capacitorCurrent of capacitor
iC(t) = dq(t)/dt = CdvC(t)/dt
Electric Resistance
基本電路元件:電 阻
電阻符號
i
V R
v = -iR
v = iRp = vi = (iR)i
= i2R = v2/R= v2G
v = -iRp = -vi = -(-iR)i
= i2R = v2/R= v2G
R: resistanceG: conductanceG = 1/R or R = 1/G
最常見的電阻符號
i+
-
V R
v = iR
A. B. C.
Electric Inductance
電感器:儲存磁通量(magnetic flux)的元件
電感器符號
+
-
i
V L
L(t)
L(t)
+
-
i
V L
L(t)
L(t)
A. B.
voltage of inductorvoltage of inductor
vL(t) = dψ(t)/dt = LdiL(t)/dt
Flux on inductorFlux on inductor
L = ψ(t) = LiL(t)
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