How voltage, current, and resistance relate : OHM's LAW
The relationship between voltage, current, and resistance is described by to solve for any unknown parameter without using any algebra. Current Amps is the flow or movement of electric charge. R resistance Ohms is the property of material to Resist or slow the movement of the. DC Circuit Theory. The fundamental relationship between voltage, current and resistance in an electrical or electronic circuit is called Ohm’s Law. Then all basic electrical or electronic circuits consist of three separate but very much related electrical quantities called.
Here are the standard units of measurement for electrical current, voltage, and resistance: The "symbol" given for each quantity is the standard alphabetical letter used to represent that quantity in an algebraic equation.
Standardized letters like these are common in the disciplines of physics and engineering, and are internationally recognized. The "unit abbreviation" for each quantity represents the alphabetical symbol used as a shorthand notation for its particular unit of measurement. Each unit of measurement is named after a famous experimenter in electricity: The amp after the Frenchman Andre M.
The mathematical symbol for each quantity is meaningful as well. The "R" for resistance and the "V" for voltage are both self-explanatory, whereas "I" for current seems a bit weird. The "I" is thought to have been meant to represent "Intensity" of electron flowand the other symbol for voltage, "E," stands for "Electromotive force.
All of these symbols are expressed using capital letters, except in cases where a quantity especially voltage or current is described in terms of a brief period of time called an "instantaneous" value. For example, the voltage of a battery, which is stable over a long period of time, will be symbolized with a capital letter "E," while the voltage peak of a lightning strike at the very instant it hits a power line would most likely be symbolized with a lower-case letter "e" or lower-case "v" to designate that value as being at a single moment in time.
This same lower-case convention holds true for current as well, the lower-case letter "i" representing current at some instant in time. Most direct-current DC measurements, however, being stable over time, will be symbolized with capital letters. One foundational unit of electrical measurement, often taught in the beginnings of electronics courses but used infrequently afterwards, is the unit of the coulomb, which is a measure of electric charge proportional to the number of electrons in an imbalanced state.
One coulomb of charge is equal to 6,,, electrons. The symbol for electric charge quantity is the capital letter "Q," with the unit of coulombs abbreviated by the capital letter "C.
What is the algebraic relationship for resistance and voltage in electric circuits?
Cast in these terms, current is the rate of electric charge motion through a conductor. As stated before, voltage is the measure of potential energy per unit charge available to motivate electrons from one point to another. Before we can precisely define what a "volt" is, we must understand how to measure this quantity we call "potential energy. Defined in these scientific terms, 1 volt is equal to 1 joule of electric potential energy per divided by 1 coulomb of charge.
And you could look at a certain part of the pipe right over here, right over here.
Ohm’s Law - How Voltage, Current, and Resistance Relate | Ohm's Law | Electronics Textbook
And you could say, well, how much water is flowing per unit time? And that amount of water that is flowing through the pipe at that point in a specific amount of time, that is analogous to current.
Current is the amount of charge, so we could say charge per unit time. Q for charge, and t for time. And intuitively you could say, how much, how much charge flowing, flowing past a point in a circuit, a point in circuit in a, let's say, unit of time, we could think of it as a second.
And so you could also think about it as coulombs per second, charge per unit time. And the idea of resistance is something could just keep that charge from flowing at an arbitrarily high rate. And if we want to go back to our water metaphor, what we could do is, we could introduce something that would impede the water, and that could be a narrowing of the pipe.
And that narrowing of the pipe would be analogous to resistance. So in this situation, once again, I have my vertical water pipe, I have opened it up, and you still would have that potential energy, which is analogous to voltage, and it would be converted to kinetic energy, and you would have a flow of water through that pipe, but now at every point in this pipe, the amount of water that's flowing past at a given moment of time is gonna be lower, because you have literally this bottleneck right over here.Voltage, Current, Resistance & Power
So this narrowing is analogous to resistance. How much charge flow impeded, impeded. And the unit here is the ohm, is the ohm, which is denoted with the Greek letter omega.
So now that we've defined these things and we have our metaphor, let's actually look at an electric circuit. So first, let me construct a battery.
Elena Hayden and Daniel Lab 22
So this is my battery. And the convention is my negative terminal is the shorter line here. So I could say that's the negative terminal, that is the positive terminal. Associated with that battery, I could have some voltage. And just to make this tangible, let's say the voltage is equal to 16 volts across this battery. And so one way to think about it is the potential energy per unit charge, let's say we have electrons here at the negative terminal, the potential energy per coulomb here is 16 volts.
These electrons, if they have a path, would go to the positive terminal. And so we can provide a path. Let me draw it like this. At first, I'm gonna not make the path available to the electrons, I'm gonna have an open circuit here. I'm gonna make this path for the electrons.
Grafton HS Physics / Elena Hayden and Daniel Lab 22
And so as long as our circuit is open like this, this is actually analogous to the closed pipe. The electrons, there is no way for them to get to the positive terminal. The amount of current in a circuit depends on the amount of voltage available to motivate the electrons, and also the amount of resistance in the circuit to oppose electron flow.
Just like voltage, resistance is a quantity relative between two points.
Volt, Amp, and Ohm To be able to make meaningful statements about these quantities in circuits, we need to be able to describe their quantities in the same way that we might quantify mass, temperature, volume, length, or any other kind of physical quantity.
Here are the standard units of measurement for electrical current, voltage, and resistance: Standardized letters like these are common in the disciplines of physics and engineering, and are internationally recognized.
Each unit of measurement is named after a famous experimenter in electricity: The amp after the Frenchman Andre M. The mathematical symbol for each quantity is meaningful as well.
Most direct-current DC measurements, however, being stable over time, will be symbolized with capital letters. Coulomb and Electric Charge One foundational unit of electrical measurement, often taught in the beginnings of electronics courses but used infrequently afterwards, is the unit of the coulomb, which is a measure of electric charge proportional to the number of electrons in an imbalanced state.
One coulomb of charge is equal to 6,,, electrons.