Difference Between Voltage and Current in Electronic Circuits for Beginners

Hello.
I am a beginner, I have already read a bit about electronics, I know more or less the principles of operation of some electronic components, but there are still things that I cannot comprehend and maybe that is why I cannot take the next steps forward in electronics, so I am asking everyone for understanding and help.

To begin with, I would like to ask you for help in explaining the principle of voltage and current in electronic systems:

1) Voltage - I often wonder why, for example, systems are powered with 9V, and others, for example, with 12V. For example, I see that if the voltage supplying a given system is 12V, it means that there is at least one element in the system that requires a voltage of 12V So, in my opinion, the supply voltage may be dependent on at least one element in the system, so let's say if there was an element in the system that would require, say, 9V, and there would be no other element that would require more than 9V, the system would only need to be powered by voltage of 9V.

2) Intensity - I cannot understand what role the current plays in the system, I see it, for example, that it is the current that powers the entire system, i.e. that it is the current that causes the entire system to work, but I do not understand what the voltage is for in this case Couldn't there be just current or voltage? Or let's say that everything should always be at the same voltage, let's say 12V, the intensity that the system always gets from the source as much as it needs?

Please explain to me where my reasoning goes in the wrong direction.

Electric voltage


Intensity

Sometimes the systems have a specific voltage, and sometimes in the range, e.g. 9-18V - It means that the system can be powered with the voltage from 9 to 18V.

As for the intensity, for electronic systems, universal power supplies for e.g. PLN 8 are most often used.

regards Krzysztof

The information from the links you sent to me is too complicated, I am asking someone for a simplified explanation.

Current - symbol I (unit A - Ampere)
I = q / t

I - current, unit A (Ampere)
q - charge, unit C (coulombs)
t - charge flow time, unit s (second)

Word description: The intensity is the ratio of the charge expressed in coulombs to the time of the charge flow.

Voltage - sibmol U (V unit - Volt)
U = R * I

U - voltage, unit V (Volt)
R - resistance, unit ? (ohms), (OM dimensions)
I - current, unit A (Ampere)

Patterns can be combined and transformed.

regards Krzysztof

Thank you very much for the answer, but I wrote earlier

Quote:

I am a beginner

and I do not understand what you are talking about. I am asking someone to answer my questions, because here my friend only gave me some formulas that did not say anything, and I would ask for specific answers to the questions

Quote:

1) Voltage - I often wonder why, for example, systems are powered with 9V, and others, e.g. with 12V. I see it, for example, that if the voltage supplying a given system is 12V, it means that there is at least one element in the system that requires just 12V voltage. So in my opinion, the supply voltage may be dependent on at least one element in the system. So let's say if there was an element in the system that would require, say, 9V, and there would be no other element that would require more than 9V, then the system it would be enough to supply only 9V.

2) Intensity - I can't understand what role the intensity plays in the system, I can see it, for example, that it is the current that powers the entire system, i.e. that it is the current that causes the whole system to work, but I just don't understand it after what is the voltage. couldn't there just be a current or a voltage? Or let's say that everything should always be at the same voltage, let's say 12V, the intensity that the system always gets from the source as much as it needs?

or ask someone understanding and contact me on my GG number 2871966, and please do not be upset if I ask trivial questions for someone.

There are three main sizes in the electrical circuit.
Voltage expressed in volts [V]
Current expressed in amperes AND and intensity is the magnitude of the current. Low current, low current, high current, high current flows.

What is needed for the electricity to flow:

1. Potential difference, otherwise known as voltage.
Voltage is a potential difference.
Suppose 300 electrons are missing at one end of the conductor and 500 at the other end.
Both points are positive but the first point is negative of the second.
And it is this difference in the number of electrons that we call voltage.
Due to this difference, an electric field is created which attracts electrons, and therefore the voltage is referred to as electric pressure.
Nature always strives for a state of equilibrium, i.e. it wants to equal the number of electrons.

2.
Connecting these two points with a wire will cause a current to flow. Under the influence of the prevailing tension. When the number of electrons at both ends of the wire is equal (the voltage is removed), the current stops flowing.

We need electricity to flow
A) tension
B) the conductor through which this current will flow.

You can imagine the flow of the current itself as the movement of electrons or ants, or if you like.
Electricity can be compared to water.
More specifically, the flow of water in liters per second under pressure or voltage.
And we can talk about a voltage at a given point (between two points) or on an element. But the voltage doesn't flow like the current.
Because it is the current that flows through the element and the voltage "occurs" between the ends of the element.
As you can see, current cannot exist without voltage.
There is no voltage, there is no current.
And it is the flow of current that does all the useful work.

Hello.
I remember my beginnings. Old history - but to the point. I recommend you Dieter Nuhrmann's book "Electronics Easier Than You Think - Circuits". Reading this book is really fun to get to know the world of electronics. The current and voltage are described in relation to the flow of water in a pipe - pipes - sounds funny, but it helps you understand what interests you. Unfortunately, the books in this series - there are several subtitles - were published quite a long time ago - 1987 - but I think you will find these items in second-hand bookstores.
Greetings.

Explain to me like a child. What is potential ???

lsd100 wrote:

Explain to me like a child. What is potential ???

Very incorrectly speaking (as for children) it is a measure of the load, expressed in [V] volts. If the battery has 9 [V] voltage, it means that the potential difference between the poles is 9 [V]. The greater the difference, the higher the voltage (because voltage is the difference).

For example, 9 [V] of the voltage between the points (wires / claddings / whatever) will be if the potential A is 0 [V] and the potential B is 9 [V]. But the same voltage will be 9 [V] between A and B if A is 10 [V] potential and B is 19 [V] potential.

It all depends on the reference point. I hope that I will bring you closer to this greatness with my amateur reasoning. And grab Nuhrman's books. I have them myself and I bought them on the allegro once upon a time.

greetings

Imagine such a huge room filled with food. This is a battery. This room has an exit (+) and an entrance (-). Next to the exit, there is a little machine that creates "little men". Every guy gets food for the road when he exits the battery. When his food pack is full the voltage is 9V (at 9V battery). This guy wants to get out of the battery (i.e. +) and go back to (-). The food reserve with which it comes back depends on the distance traveled (resistance in ? and the speed at which it arrived (i.e., the intensity A). When we combine + with - Although the road is short, its speed is so fast that it will eat all the food.

Remember that such a guy always goes back to the battery without eating. So as if he knew the road and knew how to adjust the speed. (Unless the road is too long, then it will die somewhere and disappear)

Now I will answer your question. Why are amps and volts.
Imagine a guy with a 9V battery. He got the grub for the road and begins his journey at very high speed. After a while it goes to the resistor. There he loses speed. Then he comes out of it and finds that he has little food. So it slows down so as not to waste energy. It goes into some system, does its job, and returns to the battery without food. (The battery can generate an infinite number of figures, but has a limited supply of food. No food, no men)

Now imagine there is no resistor in the circuit above. What's going on?? And the fact that the guy falls into the system with great speed and everything starts to heat up (something ala friction), the temperature is too high, the BUM system.

I'm about to finish, I have to pick up the concrete mixer ...

Ok, we go further, now we put the resistor in place but connect 2 9V batteries, so we have 18V. Now, when the load reaches the system (behind the resistor), instead of entering culturally, it "hits the door" and destroys the whole system.

PS Despite this, and so on, I do not know very much what xP current is
PS2 If I wrote something wrong, I am asking a more advanced electrician to explain to me what I misunderstood.

Does anyone have these books in pdf?

Quote:

I just can't understand what role the current plays in the system, for example I see it that the current supplies the whole system, i.e. it is the current that makes the whole system work, but I don't understand what the voltage is for in this case.

Simply put: the battery has two plates (+) and (-). If you touch your tongue, you will feel the current flowing, i.e. you will feel the value of the current. Now imagine that your language is an electronic circuit. The wetter your tongue is, the more burning you feel.

Thus, there is a close relationship between the intensity and the voltage. Now I will introduce the concept of resistance, or resistance. You could say that the resistance is your tongue, which is the electronics - the wetter the tongue, the easier the current to pass between the lamellas (+) and (-), so there is less resistance.

Do you already understand the meaning of tension and intensity?

Then maybe let's try to explain the water supply:

Imagine two such tanks connected by two pipes of different diameter, and therefore of a different cross-section. There is a different amount of water in both tanks.



When any valve is opened, water will begin to flow from the higher level tank to the lower level tank - this is due to the difference in levels in the tanks and therefore the different weight of water exerting different pressure.

The level in a given tank is potential, in a way it's the ability to do some work.

The resulting pressure difference is in our case the voltage.

After opening the valve, the water will flow from higher pressure to lower pressure (it's like pushing a beam through two teams - the beam moves where the given assembly pushes less).

A certain amount of water can flow through a given section per unit time (just like with a corridor of a given width, no more people will pass through it than can fit in the width).

This amount of fluid flowing per unit time will be the intensity in our case.

The intensity will be the greater the larger the cross-section of the pipe (because more fluid can flow per unit time).

Depending on its cross-section, length and filling, the pipe will make it difficult for the fluid to flow through it in different ways, this hindering is the resistance to the fluid:

- the cross-section increases - the passage capacity of the pipe increases - the resistance decreases
- length increases - time to travel the length of the pipe increases - resistance increases
- we fill the pipe with, for example, balls - we reduce the cross-section of the pipe - the resistance increases

the latter with balls shows materials with different resistances - the finer the balls, the more tightly the pipe cross-section is filled and the less space the fluid has to squeeze through, i.e. it has greater problems with the flow

If a larger stream of water flows through the pipe (higher intensity), then more work can be done because the fluid acts with greater force.

Pipes with different cross-sections offer different resistance to the flowing fluid. It is similar with cables of different cross-sections, the smaller the size, the more difficult it is for the current to flow through it.

Returning to the electric field. There are different amounts of electrons in different places. Each electron has an electric charge attached to it. Electrons repel each other as single-name charges. The more there are in a given place, the greater the repulsive force.
If there is a different number of electrons in two places, there is a potential difference (i.e. such a pressure difference on the electrons) and they will want to move from the place where there are more of them to the place where there are less of them. The will to move will cease when there will be the same number of electrons in both places (because the forces will balance).

In the system, the place where there are more electrons is called the negative pole and where less positive.

Since electrons are the carriers of a portion of the current (the flow of a charge of one electron in 1 second), the real current flows from the more negative to the more positive place.

In the past, the physical mechanism of the current flow was not known and it was assumed that it flows from the positive place (positive -> means better -> so this is where the current must flow) to the negative one, although it is actually the opposite.



Comparison:
---------------------------------
Fluid-impermeable wall - insulator
Pipe - guide
Valve - switch