Basic Electronics Flashcards
1
Q
How many paths for current flow are there in a Series Circuit?
A
1 path
2
Q
Ohm’s Law
A
The mathematical relationship between voltage, current, and resistance
3
Q
Short circuit
A
An incorrect path; 2 points connected together that shouldn’t be, usually resulting in excessive current flow
4
Q
Voltage
A
A force that pushes electrons to move; electrical pressure that pushes electrons through wire; difference in charge between two points
5
Q
What is the letter and measurement of Voltage?
A
E; volts
6
Q
How to find the total sum of Resistance in a Parallel Circuit if the resistance is the SAME in each branch?
A
R(t)=R/# of branches
7
Q
In a Parallel Circuit, is the total resistance more or less than the lowest branch’s resistance?
A
Less
8
Q
What determines the South/North polarity of the magnetic field?
A
Direction of the flow of voltage current
9
Q
Is Conventional Current Flow from + to - , or - to +?
A
+ to -
10
Q
Is Electron Flow from + to - , or - to +?
A
- to +
11
Q
What is the letter and measurement of Current?
A
I; amps (amperes)
12
Q
What is Current directly proportional to ?
A
Voltage (E)
13
Q
What is Current INVERSELY proportional to?
A
Resistance (R)
14
Q
What is the letter/symbol and measurement of Resistance?
A
R; ohms Ω
15
Q
How is electricity used in audio?
A
Sound is converted into a form of electricity that can then be amplified, recorded, processed and manipulated by other electrical components and circuits, then this electricity can be sent back out to create sound waves
16
Q
What is electricity?
A
Flow of electrons through an electrical conductor
17
Q
How do electrons flow?
A
They jump from atom to atom
18
Q
What are examples of good conductors?
A
Most metals; e.g. copper, gold
19
Q
What does electricity flow create?
A
Energy
20
Q
Transducer
A
Device that converts energy from one form to another
21
Q
Examples of a transducer
A
Microphone, guitar pick-up, our ears, speakers
22
Q
Insulators
A
They stop/block the flow of electricity; opposite of conductor
23
Q
Electrical conductor
A
Allows electrons to flow easily
24
Q
How do microphones transduce sound?
A
Microphones generate a tiny voltage (millivolts) to make electrons move through a wire
25
Pre-amp amplifies mini volt signal up to _____
Line level
26
How many volts is line level?
1.23
27
What's the meaning of + and ~ in voltage?
+ indicates DC, and ~ indicates AC
28
What can multimeters measuer?
Voltage, Current, Resistance
29
What is Resistance an opposition of?
AC & DC current flow
30
What is Impedance in opposition of?
Impedance opposes AC current
31
Is Resistance or Impedance considered 'frequency dependent opposition?'
Impedance
32
What is the letter and measurement of Impedance?
Z; and Ohms Ω, similar to R
33
Power
The amount of energy being used or generated in an electrical circuit of Power
34
What is the letter and measurement of Power?
P; watts
35
Current
The intensity of electron flow; literally, the number of electrons flowing through a wire in a given period of time
36
Resistance
The opposition of electrical current flow
37
If voltage goes up, ______ goes up
Current
38
If voltage goes down, ______ goes down
Current
39
What is the basic type of electrical circuit?
Series circuit
40
Series circuit
An electrical circuit that has just one loop or path for electricity to flow, and all electrons take the same path
41
Is current the same throughout a series circuit?
Yes
42
What's a simple example of a series circuit?
Christmas lights
43
Parallel circuit
An electrical circuit that has more than one path or loop/branches for electrons to take
44
Voltage in Parallel Circuits
All branches or loops of a parallel circuit have the exactly same voltage
45
What is the equation to find total resistance in a parallel circuit?
Rt= Total Volts (E) / Total Amps (I)
46
What's a simple example to parallel circuit?
AC power strip
47
Circuit breaker
Circuit breakers trip to help stop overflowing electricity from burning the house down lol
48
What is the equation to find total resistance if resistance is the same in all branches?
Rt=R / # of branches in the circuit
49
Transformers
Electrical components that uses principals of electromagnetic induction to take an existing AC voltage and current, and transform or convert it to another AC voltage with an equivalent amount of power
50
What is the core of the transformer typically made out of?
Iron
51
Primary winding
First coil of wire of the transformer, and is the input side
52
Secondary winding
Second wire of the transformer, and is the output side
53
What are the first 3 questions you should ask when troubleshooting?
1. Is it plugged in?
2. Is it turned on?
3. Is it turned up?
54
Direct Current
Electrical current with fixed polarity, therefore all electrons are flowing in the same direction
55
Alternating Current
Electrical current with changing polarity, therefore electrons change direction flow
56
What current is blocked by Transformers?
DC
57
Why is DC blocked by Transformers?
Transformers work by using electromagnetic induction due to polarity changing in AC current to create a magnetic field that moves and expands to go from primary winding to affect the secondary winding, and DC magnetic fields are unmoving because the current is fixed polarity and direction of flow is constant = no magnetic induction.
58
Why go through a Transformer?
This allows us to change the AC voltage and current levels that are being outputted by the secondary winding
59
Turns Ratio
How much AC voltage and current flows in the secondary winding versus how much flows in the primary winding is determined by how many times you wrap the wire around the iron coil
60
If you wrap primary winding 100 times, and secondary winding 100 times, what is the turns ratio?
1:1
61
What does 1:1 ratio mean in a transformer?
For every one volt applied to primary winding, you will generate one volt in the secondary winding
62
Isolation transformer
AC in = AC out; used to provide isolation between two components of a circuit (blocking DC currents), and still pass an AC signal from one side of the circuit to another; also used to isolate ground connections and eliminate "ground loop"
63
Step Up Transformer
Increasing the voltage from Primary winding to Secondary winding
AC in < AC out
64
Explain an example of what's happening with a Step Up Transformer (turn ratio)
A transformer with 100 turns of Primary windings and 400 turns of Secondary windings will create a 1:4 ratio, so for every one volt applied to the input, the output will be 4 volts
65
Step Down Transformer
Decreasing the voltage from the Primary winding to Secondary winding
AC in > AC out
66
Explain an example of what's happening with a Step Down Transformer (turn ratio)
A transformer with 100 turns of Primary windings and 10 turns of Secondary windings will create a 10:1 ratio, so for every one volt applied to the input, the output will be 1/10 volts
67
Standard AC Distribution in the US
120vAC, 60Hz, Single Phase
68
What current's symbol is ~ ?
AC
69
What current's symbol is ____
| ------- ?
DC
70
Impedance Transformer
A high impedance connection in the primary can be made to look like a low impedance connection to whatever is connected to the secondary, and vice versa (low impedance can look like high)
Unbalanced in - Balanced out
(DI Box)
71
Unbalanced
Primary winding has 2 wires, one wire is the input (with current), and the other wire is grounded
72
If it is Unbalanced, does it have high or low impedance?
High
73
Balanced
Secondary winding has two coils of wire joined in the middle - one wire with matching polarity to the primary winding (pin 2), and the other with an opposite polarity (pin 3)
74
If it is Balanced, does it have high or low impedance?
Low
75
Does Pin 1 on Impedance transformer have current or ground? If current, is it in polarity or opposite?
Pin 1 is ground
76
Does Pin 2 on Impedance transformer have current or ground? If current, is it in polarity or opposite?
Pin 2 has current and is in polarity with Primary
77
Does Pin 3 on Impedance transformer have current or ground? If current, is it in polarity or opposite?
Pin 3 has current and is in opposite polarity with Primary
78
High impedance connections are considered balanced or unbalanced?
Unbalanced
79
Low impedance connections are considered balanced or unbalanced?
Balanced
80
Electric instruments typically have high input and output impedances - what type of cables do they use?
Unbalanced 1/4" TS, Tip/Sleeve cables
81
Shield wire
Wrapped/braided around the center copper wire of the 1/4" TS & TRS cable
82
Purpose of a shield wire
It is typically hooked to the circuit ground through the device the cable is plugged into - therefore, it becomes and electrical conductor hooked to ground surrounding the signal carrying wire, and "shielding" it from electromagnetic energy
83
If you have to send your signal a longer distance, or want extremely low noise transfer, will you use an unbalanced or balanced line signal? Why?
Balanced, because they have low impedance signals
84
Balanced line signal cables have how many conductors?
3
85
Is the shield wire part of the signal circuit in a balanced line signal?
No
86
Is the shield wire part of the signal circuit in an unbalanced line signal?
Yes
87
In a balanced line cable (XLR) what is Pin 1 connected to?
Shield wire
88
In a balanced line cable (XLR) what is Pin 2?
Conductor carrying the phase signal - Hot (red)
89
In a balanced line cable (XLR) what is Pin 3?
Conductor carrying the identical but opposite polarity signal to Pin 2 - Cold (white)
90
What can we use to change an unbalanced signal to a balanced one?
A transformer
91
Do condenser mics have transformers built into them?
No, because condenser mics require phantom power (DC), which transformers block
92
What do condenser mics use to create a balanced signal?
ICA - impedance conversion amplifier
93
What is considered electronically balanced?
A condenser mic
94
What type of cable carries balanced line signals?
1/4" TRS Tip Ring Sleeve and TT Tiny Telephone connectors
95
In a 1/4" TRS, which parts are hot/red, cold, ground?
Tip: hot/red, Ring: cold, Sleeve: ground
96
Common Mode Rejection
Noise cancellation effect we get by using balanced line signals, cables & connections
97
Differential Amp
Electronically balanced input preamplifier that inverts one of the two entering signals
98
Mic cartridge generates unbalanced signal, which is converted by the built in impedance transformer to what?
A balanced line signal
99
Which two pins out of 1, 2, and 3 help transform an unbalanced signal to a balanced signal?
Pins 2 and 3
100
After being transformed to a balanced line signal, the signal travels down pins 2 & 3 on the XLR to the differential amp - now what happens to the signal?
Balanced line signal has two signals - one that is in opposite polarity to the other, when it hits the diff amp, it flips the polarity of pin 3 signal, causing it to be matching polarity with pin 2 = larger amplified signal
101
How does Common Mode Rejection work?
If noise gets past the shield wire, the noise inducing magnetic fields hit both signal carrying wires at basically the same time, so the noise voltages will have the same polarity on both wires. Because it's the same, the diff amp will invert one of the signals, causing them to be in exact opposite polarity, therefore CANCELLING NOISE
102
Common Mode Rejection Ratio
A rating of how much noise will be cancelled
103
What does CMRR rated at -75dB mean?
The noise is being attenuated by 75dB compared to the actual signal you want to amplify
104
Impedance Matching
To maximise signal transferring efficiency, we must match output impedance of device (mic, instrument, etc.) to the input impedance of the next device (amplifier, speaker, etc.)
e.g. high impedance output don't do good with low impedance input
105
Power Supplies
Converts AC to DC
106
On a standard US 120vAC outlet, there are 3 prongs. Which is which?
Left larger terminal: Neutral/common (white wire)
Right smaller terminal: Hot 120vAC (black wire)
Bottom round terminal: Earth ground (green/copper wire)
107
What is the voltage between Neutral/common wire and Hot 120vAC wire?
120vAC
108
What is the voltage between Neutral wire and Earth ground wire?
0vAC
109
What is the voltage between Earth ground wire and Hot 120vAC wire?
120vAC
110
List the 4 main reasons for Impedance matching
1. Max the transfer of power
2. Increase the headroom
3. Increase signal:noise
4. Increase efficiency
111
Series Circuit cheat sheet rules
```
I = stays the same
R = add for total
E = add for total
P = add for total
```
112
Parallel Circuit cheat sheet rules
```
I = add for total
R = total E / total I
E = stays the same
P = add for total
```
113
Electromagnetic Induction
A principle that a coil of wire moving through a magnetic field, or vice versa, will induce/generate an AC current
114
Does unbalanced or balanced have 1 signal wire?
Unbalanced
115
1/4" TS (tip, sleeve) and examples
Cable used for unbalanced line signals
| Instrument cables, shorter cable runs
116
1/4" TRS (tip, ring, sleeve) and examples
Cable used for balanced line signals
| XLR (mic cable), longer cable runs
117
What is a big benefit of balanced line signals?
CMRR - Common mode rejection ratio
118
Does a preamp or a power amp have a higher voltage gain?
Preamp
