Analogue Electronics Flashcards
1
Q
A parralel-plate capacitor consists of…?
A
Two conductive plates seperated by a dielectric layer
2
Q
Does net charge cross a capictor?
A
No
3
Q
What do capacitors try to do to the voltage across the plate?
A
Try to keep it constant
4
Q
What does the cicrcuit symbol for capacitance look like?
A
5
Q
What does a capacitor represent in terms of fluid flow analogy?
A
A capacitor represents a reservoir with an elastic membrane separating the intlet and outlet
6
Q
What is the equation for charge?
A
q=Cv
7
Q
What is the relationship between current and voltage?
A
8
Q
v(t) = ?
A
9
Q
This is the graph of voltage vs time, what would charge vs time and current vs time look like?
A
10
Q
Voltage is the intergral of…?
A
Current
11
Q
w(t) = ?
A
w(t) = ½vq = q2 /2c =
12
Q
If this is v-t, what would i-t, p-t and w-t look like?
A
13
Q
A
14
Q
How do you work out the total capacitance for capacitors in parralel?
A
Add them up (suppose to be C3 - it’s in the book)
15
Q
How do you work out the total capacitance for capacitors in series?
A
1/C
16
Q
What’s the equation for the capacitance of a parallel plate capacitor?
A
17
Q
What does an inductor look like?
A
18
Q
Basic equations for inductor/conductance?
A
19
Q
How do you work out inductors in series and in parallel?
A
- In series
- You add them
- In parallel
- You do 1/L
It’s exactly the same as resistors!
20
Q
Capacitors don’t like…?
A
Instantaneous changes in voltage
21
Q
Inductors don’t like…?
A
Instantaneous changes in current
22
Q
V1(t) = ?
A
V1(t) = Vs(1-e-t/2)
23
Q
2 equations
A
L/R and
24
Q
3 equations
A
And V = IR & V = CR
25
26
For infinite steady state; (what type of circuit)
* Inductors = ?
* Capcitors = ?
* Voltage across the capacitor = ?
* Inductors = closed/short circuit
* Capacitors = Open circuit
* 0V
27
How is the homogeneous equation obtained?
By setting the forcing function to zero
28
1. What is the forcing function?
2. And if we have a circuit without sources, what is the forcing function?
3. And what is the forcing function for dc sources?
1. A function of only resistances and the inductance (or capacitance)
2. 0
3. Constant
29
How is the natural response obtained?
By solving the homogeneous equation
30
VRMS = ?
31
cos2(z) = ?
(1 + cos(2z))/2
32
How do you solve phasers?
1. Determine the phasors
2. Change the phasors to cartesian (rectangular) form
3. Add Re and Im part
4. Express sum as phason (polar form)
5. Express as a time (cos) function
33
* Leading is...
* Lagging is...
* Leading is **infront**
* Lagging is **behind**
34
* R = ?
* Z (\_\_\_\_ \_\_\_\_) = ? = ?
* R = V/I
* Z (Complex impeadance) = V/I = jWL
35
ZL = ?
Current lags
36
Zc = ?
Voltage lags
37
w (omega) = ? (two equations)
= 2π/T
38
f = ?
f = 1/T
39
v(t) = ? (cos one)
40
sin(z) = ? (for degrees and radions)
41
Vrms = ?
42
Pavg = ?
Pavg = I2rmsR
43
V = ? so ?(diff) = ? so eventually = ?
44
What does V1 lead V2 by?
60°
45
For a **pure resistance**, current and voltage are...?
In phase
46
What do power triangles for ****
1. **Inductive** loads
2. **Capacitive** loads
Look like?
47
What does the **Thévenin equivalent** for an **ac** **circuit** consist of?
A **phasor voltage source, Vt,** in **series** with a **complex impedance Z**
48
What does a **Norton equivalent circuit** consist of?
A **phasor current source** in in **parallel** with the **complex impedance Zt**
49
Averge power over a period P =?
50
Irms = ?
51
What would a balanced 3 phase voltage source look like?
52
P = ? (resistance equations)
P = I2R and P = V2/R
53
The term cosØ is called...?
**Power factor** or **power angle**
54
Reactive power Q = ?
Q = VrmsIrmssin(Ø)
55
Vm = ?
w(omega) = ?
Ø = ?
Vm = Maximum value
w(omega) = Angular frequency (Rad/s)
Ø = Phase angle
56
Power traingle for inductive loads? (ø positive)
57
Power triangle for Capacitive load? (ø negative)
58
Triangle for z?
59
The impeadance z = ? (additional power relationships)
60
In this equation
P = V2Rrms/R
VRrms is the...?
VRrms is the rms voltage **across the resistance**
61
In this equation
Q = V2Xrms/X
VXrms is the...?
VXrms is the rms voltage **across the reactance**
62
X is ____ for inductance
X is negative for \_\_\_\_
X is **_positive_** for inductance
X is negative for **_conductance_**
63
In Thévenin Equivalent Circuits,
Vt = ?
Zt = ?
Vt = Voc
Zt = Voc/Isc = Vt/Isc
64
If the circuit has ____ ***and*** ____ sources,
Rth (Thévenin) = ?
If the circuit has **_independent_** ***and*** **_dependent_** sources,
Rth (Thévenin) = RN = Voc/Isc
65
Isc = ?
Isc =
Ohm's Law = V/R
66
This is a Thévenin equivalent circuit, what would a Norton equivalent circuit look like?
67
If the circuit has ***only*** ____ sources,
Vth = ?
IN = ?
Rth = Rn = ? ⇒ ___ \_ ______ \_\_ ___ \_\_\_\_\_\_\_
If you had a **voltage** **source** you work out the...?
If you add a **current** **source** you work out the...?
If the circuit has ***only*** **_dependant_** sources,
Vth = 0
IN = 0
Rth = Rn = ? ⇒ **_add a source to the circuit_**
If you had a **voltage** **source** you work out the...**_current_**
If you add a **current** **source** you work out the...**_voltage_**
68
There are **3 different scenarios** to find **Rn (R Norton)** and **RTh (R Thévenin)**, how do you do it when there's...
1. Only **_independent_** sources
2. Only **_dependent_** sources
3. Both **_dependent_** and **_independent_** sources
There are **3 different scenarios** to find **Rn (R Norton)** and **RTh (R Thévenin)**, how do you do it when there's...
1. Only **_independent_** sources
* Kill all the sources and find Req
2. Only **_dependent_** sources
* Add a **source**
* If it's a **current** **source** you find **voltage** using **Ohm's** **law**,
* If it's a **voltage** **source** you find **current** using **Ohm's** law
3. Both **_dependent_** and **_independent_** sources
* Voc/Isc
69
Vth = ?
IN = ?
Vth = Voc
IN = Isc
70
What would the Thévenin equivlent circuit look like?
71
What would the Norton equivalent circuit look like?
72
What is the **superposition principle?**
The **superposition principle** states that the **total response** is the **sum of the responses** to each of the **independent** **sources** **acting** **individually**
73
The thèvenin voltage is equal to the...?
...open circuit voltage
Vt = Voc
74
When sources are zeroed, current sources become ____ \_\_\_\_ and voltage sources become ____ \_\_\_\_\_
When sources are zeroed, current sources become **_open circuits_** and voltage sources become **_short circuits_**
75
Pavg = ? = ?
Pavg = V2rms/R = I2rmsR
76
Total energy absorbed, w = ?
w = ∫ p(t) dt
77
What resistance value should be chosen for RL to achieve maximum power transfer from the circuit to the load?
The **Thévenin equivalent resistor**
