Energy Basics Flashcards
Understand basics of energy and fundamental value chain
What is electricity?
Electricity is a flow of electrons trough a conductor
Ohm’s Law (Current formula - rate at which electrons flow)
I (Current) = U (Voltage) / R (Resistance)
Current (Ampere - A): the rate at which electrons flow through a conductor
Voltage (Volt- V): The force that moves electrons (potential difference)
Resistance (Ohm): degree by which materials oppose to electric
What are the other types of energy that electricity can be converted in?
- Mechanical energy - effect: magnetism - applicability: electric motors
- Thermal energy - effect: Heat - applicability: incandescent light bulb
- Electromagnetic energy - effect: light - applicability: flourescent light bulb
- Electric energy - effect: information transfer - applicability: transistor chips controlling electricity flows, numer 0 and 1
The fomula of Power (Watt amount of electricity) is:
P (Power) = U (Voltage) x I (current)
Power (Watt - W): amount of electricity required to perform a certain task (to move electrons through a specific device)
Current (Ampere - A): the rate at which electrons flow through a conductor
Voltage (Volt - V): the force that moves electrons
Describe the characteristics of direct current
- Electrons flow in one direction
- Direction of current does not change over time
- Generated by electrochemical or photovoltaic sources
Describe the characteristics of alterating current
- Electrons change flow direction over time
- Turns per minute drive frequency of electrons changing flow direction
- Generated by electromagnetic power sources
What are transformers?
Transformers are electrical devices used to change the voltage level of an electrical current
How does a transformer work?
- Electricity at high voltage is run through a number or wires around an iron core
- Alternating current leads to an alternating magnetism in the core
- The changing magnetism creates current in the neighboring wires
- The lower number of wires leads to a lower voltage
Mention the 3 steps of the electrical delivery system
- Generation:
- The flow of electrons is created with voltages of several thousand volts
- Voltage is stepped up by a transformer - Transmission
- Conductor lines of super high voltages
- Step-down transformers reduce the voltage of the current flow in customers areas - Distribution
- Conductor lines of lower voltages
- Services lines lead the power to customers buildings
- At interconnection with services lines, transformers change the voltage to needed level
- Through meters and customers’ internal wiring system, electricity is directed to electric devices
What is needed to transport a higher power through a given conductor?
One needs to increase the voltage. The current (I) depends on and is limited by the conductor’s features
What will happen if the voltage is doubled?
A 4 times higher power can be transmited through the same given conductor
P (power) = U2 (voltage) / R (Resistance)
What is the relationship between transmission loss generated by the current flowing through a conductor and the materials’ resistance?
AU (voltage loss) = I x R
By keeping a lower current the transmission loss can be reduced, making the process more efficient
The 4 key physical properties that make electricity a unique commodity are:
- Electricity can hardly be stored
- The path followed by electricity is difficult to follow: electrons follow the path of least resistance
- Disturbances are quickly transmitted and hard to isolate: electricity flow at speed of light, isolating a disturbance could be done only by breaking the circuit
- Significant voltage or frequency fluctuations are not acceptable: electric devices don’t tolerate fluctuations in voltage or frequency
types of energy
chemical, electrical, electromagnetic, nuclear, mechanical, thermal
