Test 1 Flashcards
Impedance opposes ___ and ___ of ____ field.
Strength, charge, electric field.
2 field we’re interested in for audio.
Electric & Magnetic
Inductance opposes change in ___ and ___ of ___ field.
Strength, polarity, magnetic
Magnetic Field
Inductance
Electric Field
Capacitance
Speed at which electricity travels in a wire is called. What % of the speed of light.
Propagation Velocity, 70%
For a cable to be electrically short it must be ___, or less, of the maximum frequency of interest. If it is, it’s not ___
10%, Transmission Line
Why was grounding originally created.
Prevent death by lightning strokes, and industrial created static charge.
Grnd connected to the earth via a low resistance path.
Earth Grnd
What ground protects against lightning strikes.
Earth Grnd
Ground that prevents electrocution due to potentially faulty electronics in a device.
Safety (Fault) Ground.
Grounding scheme used for frequencies below 1 MHz.
Single Point (Star) Grounding.
Grounding scheme used for frequencies above 1 MHz.
Multipoint (Mesh) Grounding.
Grounding scheme used for frequencies above & below 1 MHz with equal effectiveness.
Frequency selective transmission (hybrid) grounding.
There should always be a shield grounding at the driven end of the cable whether or not the end connected to a receiving device is balanced or not. T or F
True.
3 basic types of grounding.
Earth, safety, and signal grounding.
Impedance is the ___ effect of both resistance & reactance of circuits that contain inductance, capacitance, and resistance.
Combined.
There’s a predictable amount of noise generated by all devices. T or F
True.
Name of measured amount of noise in each device.
Inherent Noise.
Inherent noise connect in signal path from two separate devices add. T or F.
True.
Noise can or cannot be removed from original signal without altering it.
Can’t.
Inductance is denoted ___
L
Field that neither moves nor changes direction is ____.
Static.
If one type of field moves or fluctuates in space the other type of field is generated. T or F
True.
___ ___ is the movement of electrons.
Current flow.
For current to flow it must leave and return to a source. T or F
True.
EMF ___ ___ ___ is commonly know as ___ and is denoted _
Electro Motive Force, Voltage, V
Current if commonly denoted _ for ___
I, intensity.
Unit of measurement for current.
Amps. A
Resistance is denoted _. Measure in ___ denoted___.
R, ohms, omega.
Electrostatic field exists between any 2 conductors that have a ___ between them.
Voltage.
Anything that transfers electricity.
Conductor.
Capacitance is the property that tends to oppose change in the ___ or ___ of the ___ static field.
Strength, charge, electrico
Capacitance is denoted _ unit of measurement ___ denoted _.
C, Farads, F
Inductance is denoted _. Measured in ___ denoted _.
L, Henry’s, H
Impedance is denoted _. Measured in ___.
Z, ohms
All real world circuits contain ___ ___ ___ ___.
Capacitance, inductance, resistance, and impedance.
SCIN. Type of cable that has the least SCIN?
Shield Current Induced Noise. Braided shields
Devices called ground isolators solve what two problems.
Ground loop and common Z problems.
A transformer fits or doesn’t fit the definition of a ground isolator?
Fits.
Twisting of conductors in a balanced line pair values their their resistance to magnetic field. T or F
True.
An interface consists of ___ ____ ___
Driver -> line -> receiver.
Any voltage that’s the same on both conductors of a single circuit is said to be ___ of both circuits.
Common
A balanced circuits rejecting what kind of noise?
Common mode noise
Differential circuit is a balanced circuit which gives us ___
Differential gain & common mode gain
CMRR is the ratio of ___?
Differential gain to the common mode gain
Inductive coupling results when any conductor cuts the ___ lines of force.
Magnetic
When a conductor cuts a magnetic line of force, what is generated through inductance?
Voltage
Real world CMRR would contrast significantly from spec sheets. T or F
True
A concise definition of a balance circuit is?
A 2 conductor circuit with a shield.
All circuits connected to conductors must have the same ___
Impedance.
The purpose of balancing is to make noise pick up equal in ___ conductors?
Both, in which case it can be a common mode signal.
A differential devices will reject what voltage.
Common mode.
2 signals are said to have ___ when they have equal magnitude but opposite polarity.
Symmetry.
What advantage does signal symmetry give us?
Increases our output level.
Noise cancelation comes from ___ signals?
Common Mode.
Symmetrical signals give us ___ signal?
Differential.
