tags:
- video
- notes
- electronics
- electricity
source: https://www.youtube.com/watch?v=X_crwFuPht4&ab_channel=AlphaPhoenix
created: 2024-11-02
published: 2023-09-08What happens to voltage as electricity flows through a wire?
As electricity flows through a wire, the voltage decreases proportionally to the length away from the starting terminal.
What happens to voltage as electricity flows through a wire with a resistor in the middle?
As electricity flows through a wire with a resistor in the middle, the voltage:
- Decreases along the first half of the wire.
- Decreases greatly at the resistor causing it to be released as heat.
- Decreases along the second half of the wire.
What is the equation for Ohm's Law?
The equation for Ohm's Law is
What are the three variables in Ohm's Law?
The three variables in Ohm's Law are:
- Voltage (measured in volts). - Current (measured in amps). - Resistance (measured in ohms).
What is current?
Current is a measurement of charged flow per unit of time.
What does current measure in a wire?
In a wire, current measures the number of electrons that pass by a certain point in that wire in a given time frame.
What unit is current measured in?
Current is measured in amps.What is one amp equal to?
One amp is equal to one coulomb per second.How many electrons are in one coulomb? (1)
One coulomb haselectrons.
What is the average speed of electrons flowing through a wire if the current is one amp?
If the current is one amp, the average speed of electrons flowing through a wire is ~0.25 millimeters per second.
What is the average speed of electrons flowing through a wire if the current is four amps?
If the current is four amps, the average speed of electrons flowing through a wire is ~1 millimeters per second.What is another term for the average speed of electrons moving through a conductor?
Another term for the average speed of electrons moving through a conductor is drift velocity.
Electron drift
Electrons move through a conductor (like a wire) when there's a voltage applied. But, they move very slowly. This slow movement is called drift velocity and is typically only a few millimeters per second in a wire.
Signal propagation at near light speed
While individual electrons move slowly, the electrical signal (or the effect of applying voltage) moves through the wire nearly at the speed of light. That's because the signal is carried by an electromagnetic wave that propagates along the conductor.
When you apply a voltage at one end of a wire, this creates an electromagnetic field, and it is this field that pushes the electrons forward. The field moves at a speed close to that of light in a vacuum, though a bit slower due to the material of the wire.
How this works
Imagine each electron as a bead in a tube. If you push one bead at one end, the force gets transmitted to all the beads, moving them slightly almost instantaneously. Although each bead only moves a little, the "push" travels through the entire length of the tube quickly.
Similarly, the electromagnetic field generated by voltage propagates instantly across the conductor, influencing all electrons along the wire even though individual electrons barely move.
What do electrons encounter as they move through a wire?
As electrons move through a wire, they encounter resistance.
What is resistance?
Resistance is a pseudo-frictional force that slows down electrons in a wire and dissipates electrical energy as heat.
What is the classical view of electrical resistance?
The classical view of electrical resistance is like a Plinko board where electrons want to move from one side of a conductor to another but there's a lattice of obstacles like atomic nuclei which are in the way.
What is happening as the electrons are moving through the lattice of obstacles?
As the electrons are moving through the lattice of obstacles, the lattice is continuously vibrating.What happens when an electron hits an obstacle?
When an electron hits an obstacle, it gets propelled in a random direction.What happens when two electrons in a wire move in opposite directions at the same speed?
When two electrons in a wire move in opposite directions at the same speed, their effects cancel out.What's the only thing we can measure since the electrons are colliding with obstacles and scattering in random directions as they move through a conductor?
Since the electrons are colliding with obstacles and scattering in random directions as they move through a conductor, the only thing we can measure is the average speed of the electrons.Can electrical components detect the difference between electrons sitting still and two electrons moving in opposite directions?
No, electrical components can't detect the difference between electrons sitting still and two electrons moving in opposite directions.
What is voltage?
Voltage is a term that describes how much energy an electron would gain if it moved from one location to another completely unrestricted.
In circuits, voltage is always a ... measurement.
In circuits, voltage is always a relative measurement.
What is voltage proportional to?
Voltage is proportional to the density of excess electrons at any given location.
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Is voltage a force?
No, voltage isn't a force.
What is the force that pushes electrons from one end of a wire to another?
The force that pushes electrons from one end of a wire to another is the coulombic force.
Is a volt a unit of energy?
No, a volt isn't a unit of energy.
What is voltage equivalent to if you're comparing electrostatic potential energy to gravitational potential energy?
If you're comparing electrostatic potential energy to gravitational potential energy, voltage is equivalent to height.
How could voltage be explained using an analogy of a ball going down a hill?
Using an analogy of a ball going down a hill, voltage could be explained as the height of a hill that an electron is pushed up to before rolling back down.
What is the equation for electrostatic potential?
The equation for electrostatic potential is
What is an electron volt using the analogy of a ball going down a hill?
Using the analogy of a ball going down a hill, an electron volt is a unit of energy equivalent to the kinetic energy of one electron being pushed down a hill that is one volt tall.
How many joules is an electron volt (eV)?
An eV isjoules.
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In the analogy of the ball and the hill, what does the electron consider to be the hill?
In the analogy of the ball and the hill, the electron considers anything that's charged, including other electrons, to be the hill.
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Where is the potential energy from two electrons being pushed together stored?
The potential energy from two electrons being pushed together is stored in the electric field around the electrons.
What is the equation for the amount of energy stored in an electric field?
The equation for the amount of energy stored in an electric field is
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