24 Questions
What does a transmission line do?
Transfers electrical energy from one point to another
Which of the following is NOT a type of transmission line mentioned in the text?
Optical fiber
What is the purpose of defining characteristic impedance in a transmission line?
To match impedance for signal transfer efficiency
Which of the following is included in the learning objectives for this module?
Identify categories of transmission media
What is the formula used to calculate characteristic impedance in a transmission line, as mentioned in the text?
$Z_c = \sqrt{\frac{L}{C}}$
What is one of the deliverables listed under assessment for this module?
Answer drill exercises at the end of the module
What is the advantage of using a balanced (Parallel-Conductor) Transmission Line in terms of construction?
Simple construction
Why are non-conductive spacers placed at periodic intervals in a Balanced (Parallel-Conductor) Transmission Line?
For support and to keep distance between the conductors
What is a characteristic feature of a Twin Lead transmission line?
It uses continuous solid dielectric spacers
Why are neighboring pairs in Twisted Pair transmission lines twisted with different pitch?
To decrease interference due to mutual inductance
Which type of transmission line is sometimes referred to as 'ladder line'?
Open-Wire
What does the presence of an air gap between parallel wires in Open-Wire Transmission Lines help achieve?
Cost-effective insulation when space is not a big issue
What type of cable is commonly used in TV broadcast?
Rigid-air filled coaxial cable
In what applications are shielded twisted pair cables commonly used?
Security systems to avoid interference
What is the purpose of the conductive metal braid in shielded twisted pair cables?
To act as a shield against interference
What is the insulating material in a flexible coaxial cable primarily made of?
Air
Why are twisted-pair cables used in recording studios or public address systems?
To assure a balanced audio configuration
Which type of cable is used as a transmission line for radio frequency signals?
Flexible coaxial cable
What is the characteristic impedance of a transmission line?
Impedance seen looking at an infinitely long transmission line
What is the Dielectric Loss in a transmission line mainly caused by?
Difference in potential between two conductors
What is the type of loss that occurs when the electromagnetic field cuts through a nearby metallic object?
Radiation Loss
In a transmission line, what causes Corona discharge to happen?
Exceeding the breakdown voltage between conductors
What is another term for Conductor Loss in a transmission line?
I2R Loss
Which factor determines the characteristic impedance of a coaxial line?
Presence of dielectric material
Study Notes
Transmission Line Definition and Classification
- Transmission line: any means of conveying signal or power from one point to another
- Metallic conductor system used to transfer electrical energy from one point to another
Types of Transmission Line
- Balanced transmission line: used when balanced properties are considered
- Examples:
- Open-Wire Transmission Lines (simple, used for radio signals and power transmission)
- Twin Lead (ribbon cable, continuous solid dielectric, used for radio transmitters and receivers)
- Twisted pair (formed by twisting two insulated conductors, used in networking and communication)
- Shielded Cable pair (twisted-pair enclosed in a conductive metal braid, used in security systems and audio configuration)
- Examples:
- Unbalanced transmission line: used when unbalanced properties are considered
- Coaxial transmission lines:
- Rigid-Air Filled (center conductor surrounded by a tubular outer conductor, used in TV broadcast)
- Flexible Coaxial Cable (outer conductor is braided, flexible, and coaxial to the center conductor, used in radio frequency signals, computer networks, and cable television)
Transmission Line Equivalent Circuit
- Characteristic Impedance (Zo):
- Definition: impedance seen looking at an infinitely long transmission line or the impedance seen into a finite length of line terminated in a purely resistive load equal to the characteristic impedance of the line
- Formula for Two-Parallel Wire Line and Coaxial Line
Transmission Line Losses
- Conductor (Copper) Loss (I2R loss): energy dissipated in the form of heat due to current flowing through conductors
- Dielectric Losses: loss due to difference in potential between two conductors of the transmission line
- Radiation or Induction Loss: loss caused by the fields surrounding the conductors
- Corona: luminous discharge that occurs between the two conductors of a transmission line when the difference of potential between them exceeds the breakdown voltage
This quiz covers topics related to transmission lines such as definition, types (balanced and unbalanced), equivalent circuit, characteristic impedance, mathematical model for calculating characteristic impedance, velocity factor, and transmission line losses. Get ready to test your knowledge!
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
