As soon as we start studying school curriculum physics, almost immediately our teachers begin to tell us that between current and voltage there is a very a big difference, and we really need its knowledge in later life. And yet, now even an adult cannot tell about the differences between the two concepts. But everyone needs to know this difference, because we deal with current and voltage Everyday life, for example, by plugging in a TV or phone charger.
Definition
Electric shock called the process when under the influence electric field the ordered movement of charged particles begins. Particles can be the most different elements, it all depends on specific case. If we are talking about conductors, then the particles in this situation are electrons. Studying electricity, people began to understand that the capabilities of current allow it to be used in the most different areas, including medicine. After all, electrical charges help to resuscitate patients and restore heart function. In addition, current is used in the treatment of complex diseases such as epilepsy or Parkinson's disease. In everyday life, electric current is simply irreplaceable, because with its help the lights are on in our apartments and houses and electrical appliances work.
Voltage- a concept much more complex than current. Single positive charges move from different points: from low to high potential. And voltage is the energy spent on this movement. For ease of understanding, an example is often given with the flow of water between two banks: the current is the flow of water itself, and the voltage shows the difference in levels in the two banks. Accordingly, the flow will continue until the levels are equal.
Difference
Probably, the main difference between current and voltage could be noticed already from the definition. But for convenience, we will present two main differences between the concepts under consideration with a more detailed description:
- Current is a quantity of electricity, while voltage is a measure potential energy. In other words, both of these concepts are highly dependent on each other, but at the same time they are very different. I (current) = U (voltage) / R (resistance). This is the main formula by which you can calculate the dependence of current on voltage. Resistance is affected whole line factors, including the material from which the conductor is made, temperature, external conditions.
- The difference is in the receipt. Exposure to electrical charges in various devices (such as batteries or generators) creates voltage. And the current is obtained by applying voltage between the points of the circuit.
To understand all this, let us recall the exact definitions from the reference book (memorizing them is very useful). So, the current, or rather its magnitude, is the amount of charge passing through the cross-section of the conductor per unit time: I = Qlt. The unit of current is called ampere and its unit is coulombs per second. Knowing this fact will be useful to us later. The story with voltage will be much more complicated - the magnitude of voltage is the potential difference between two points of matter. It is measured in volts, and the unit of measurement is the joule.
per pendant. Why this is so is easy to understand when immersed in understanding precise definition voltage value: 1 volt is such a potential difference at which the movement of a charge of 1 coulomb will require energy expenditure, which will be equal to 1 joule.
All this can be perfectly imagined by comparing a conductor and a pipe through which water flows. Using this comparison, we see that the current value can be easily imagined as the amount of water flowing per second (this is a wonderful analogy in its accuracy), then the voltage is like the pressure difference at the outlet and inlet of our pipe. Typically the pipe ends in an open drain, so the outlet pressure will be atmospheric pressure, and it can be taken as reference level. In the same way in electrical diagrams there is a common wire (or “common bus” - for brevity it is called “ground”, although this is incorrect, the potential of which is taken as zero, and against which all voltages in the circuit are measured. Usually (but not always!) the negative wire is taken as the common wire output of the main power supply of the circuit.
So, let's return to the question of how to distinguish current from voltage? It would be correct to say this: current is the amount of electricity, and voltage is a measure of potential energy. A person who does not understand physics, of course, will begin to shake his head, trying to understand, then you will add: imagine a stone that falls. If a rock is small (low amount of electricity) but falls from a height (high voltage), it can create an impact as powerful as a large rock (lot of electricity) falling from a modest height (low voltage).
In fact, the example with a stone is beautiful, but not accurate - a pipe with flowing water reflects the process much more accurately. You need to know that voltage and current are usually interrelated. (I use the word “usually” because in some cases - voltage or current sources - they try to get rid of these connections, even if they never succeed completely.) Yes, yes, if we return to the example with water in a pipe, it is easy to get an idea: how with increasing pressure in the pipe (tension) the amount of flowing water(current). To put it another way, why do we need to use pumps? It's harder to imagine exactly inverse relationship- how current can affect voltage. To do this, you need to understand the very essence of resistance.
In the first half of the nineteenth century, physicists did not know how to characterize the dependence of current on voltage. There is a simple explanation for this. Try to find out experimentally what this dependence looks like.
Only thanks to the talent of Georg Ohm was it possible to see the true nature of resistance behind all the thickets and obstacles. That is, it can be concluded that the dependence of current on voltage can be described by the formula: I = U/R. The value of resistance R depends on the material from which the conductor is made and on the external conditions in the environment - especially on temperature.
Current is the directed movement of electrons (charged particles). It occurs if there is a potential difference in the circuit, that is, on one side of the conductor electric current an excess of charged particles, and on the other hand, a lack of them. The potential difference that allows electric current to flow through a conductor is voltage. Without voltage occurring, there will be no electric current.
In physics, this relationship is expressed by the formula I=U/R, where I is the current strength in the conductor, U is the voltage at the ends of this electrical circuit, and R is the resistance of this circuit. The higher the voltage in the circuit, the more charged particles will pass through it and vice versa.
As soon as we begin to study physics in the school curriculum, almost immediately teachers begin to tell us that there is a very big difference between current and voltage, and we will desperately need its knowledge in later life. And yet, now even an adult cannot tell about the differences between the two concepts. But everyone needs to know this difference, because we deal with current and voltage in everyday life, for example, when plugging in a TV or phone charger into a socket.
Electric shock is the process when, under the influence of an electric field, the ordered movement of charged particles begins. Particles can be a variety of elements, it all depends on the specific case. If we are talking about conductors, then the particles in this situation are electrons. By studying electricity, people began to understand that the capabilities of current allow it to be used in a variety of fields, including medicine. After all, electrical charges help to resuscitate patients and restore heart function. In addition, current is used in the treatment of complex diseases such as epilepsy or Parkinson's disease. In everyday life, electric current is simply irreplaceable, because with its help the lights are on in our apartments and houses and electrical appliances work.
Voltage- a concept much more complex than current. Single positive charges move from different points: from low to high potential. And voltage is the energy spent on this movement. For ease of understanding, an example is often given with the flow of water between two banks: the current is the flow of water itself, and the voltage shows the difference in levels in the two banks. Accordingly, the flow will continue until the levels are equal.
What is the difference between current and voltage
Probably, the main difference between current and voltage could be noticed already from the definition. But for convenience, we will present two main differences between the concepts under consideration with a more detailed description:
Current is an amount of electricity, while voltage is a measure of potential energy. In other words, both of these concepts are highly dependent on each other, but at the same time they are very different. I (current) = U (voltage) / R (resistance). This is the main formula by which you can calculate the dependence of current on voltage. Resistance is affected by a number of factors, including the material from which the conductor is made, temperature, and external conditions.
The difference is in the receipt. Exposure to electrical charges in various devices (such as batteries or generators) creates voltage. And the current is obtained by applying voltage between the points of the circuit.
Conclusions:
The difference between current and voltage lies in the definition, but both concepts are highly dependent on each other.
They are obtained as a result of different processes.
Many of us, even from school, cannot understand what aspects distinguish current from voltage. Of course, teachers constantly argued that the difference between these two concepts is simply enormous. However, only some adults have the opportunity to boast of having the relevant knowledge, and if you are not one of them, then it’s time for you to pay attention to our review today.
What is current and voltage?
In order to talk about what current strength is and what nuances may be associated with it, we consider it necessary to draw your attention to what it is in itself. Current is a process during which, under direct impact electric field, the movement of certain charged particles begins to occur. The latter may be a whole list of various elements; in this regard, everything depends on the specific situation. So, for example, if we are talking about conductors, then in this case, electrons will act as the above-mentioned particles. 
Perhaps some of you did not know this, but current is actively used in modern medicine and in particular in order to save a person from a whole list of all kinds of diseases, the same epilepsy, for example. Current is also indispensable in everyday life, because with its help, the lights are on in your home and some electrical appliances work. Current strength, in turn, implies a certain physical quantity. It is designated by the symbol I. 
In the case of voltage, everything is much more complicated, even if you compare it with such a concept as “current strength”. There are single positive charges that must move from different points. In addition, voltage is the energy through which the above-mentioned movement occurs. In schools, to understand this concept, they often give the example of the flow of water that occurs between two banks. In this situation, the current will be the flow of water itself, while the voltage will be able to show the difference in levels in these two banks. Therefore, the flow will be observed until both levels in the banks are equal.
What is the difference between current and voltage?
We dare to suggest that the main difference between these two concepts is their immediate definition:
- The words “current” and “current”, in particular, represent a certain amount of electricity, while voltage is usually considered a measure of potential energy. In simple words, these two concepts depend quite strongly on each other, retaining some distinctive features, with all this. Their resistance is influenced by a huge number of different factors. The most important of them is the material from which a particular conductor is made, external conditions, and temperature.
- There is also some difference in receiving them. So, if the effect on electric charges creates a voltage, then the current is obtained by applying voltage between the points of the circuit. By the way, such devices can be ordinary batteries or more advanced and convenient generators. For this reason, we can say that the main differences between these two concepts come down to their definition, as well as the fact that they are obtained as a result of completely different processes.
Current should not be confused with energy consumption. These concepts are completely different and their main difference should be perceived precisely power. So, in the event that the voltage is intended for that. to characterize potential energy, then in the case of current, this energy will already be kinetic. In our, modern realities, the vast majority of pipes correspond to analogies from the world of electricity. We are talking about the load that is created when a light bulb or the same TV is connected to the network. During this, a consumption of electricity is created, which ultimately leads to the appearance of current.
Of course, if you do not connect any electrical appliances to the outlet, the voltage will remain unchanged, while the current will be zero. Well, if there is no provision for flow, then how can we even talk about current and any of its strength? Therefore, current is just a certain amount of electricity, while voltage is considered a measure of the potential energy of a certain source of electricity.
Voltage and current are quantitative concepts that should always be kept in mind when it comes to an electronic circuit. They usually change over time, otherwise the operation of the circuit is not of interest.
Voltage ( symbol U, sometimes E). Voltage between two points is the energy (or work) expended to move a unit positive charge from a low potential point to a high potential point (i.e. the first point has a more negative potential compared to the second). In other words, it is the energy that is released when a unit charge “slides” from high potential to low. Voltage is also called potential difference or electromotive force. The unit of measurement for voltage is the volt. Typically, voltage is measured in volts (V), kilovolts, millivolts or microvolts (see section “Prefixes for forming multiples and submultiple units measurements", printed small print). In order to move a charge of 1 coulomb between points having a potential difference of 1 volt, it is necessary to do 1 joule of work. (The coulomb serves as a unit of measurement for electrical charge and equal to charge approximately electrons.) Voltages measured in nanovolts or megavolts are rare; you will see this after reading the entire book.
We give names to generator voltage triggers such as battery and batteries. Other appliances, such as a refrigerator, washing machine, iron, blender, do not have such a button that allows you to adjust the voltage. If one of these devices is turned on at a voltage higher than the voltage specified by the manufacturer, it will burn almost immediately.
If it is connected to a voltage lower than specified, or the device does not work or performs poorly. Power is electrical quantity, which indicates the electrical energy consumption of the device at each moment of its operation. For example, if a lamp is rated at 100 watts, that means it consumes 100 joules of electricity every second. Most electrical appliances only have a wattage value, but there are some that provide more than one value, such as an electric shower.
Current (symbol). Current is the speed of movement of an electric charge at a point. The unit of measurement for current is ampere. Current is usually measured in amperes (A), milliamps, microamps
Nanoamps and sometimes picoamps. A current of 1 ampere is created by moving a charge of 1 coulomb in a time of 1 s. It is agreed that current in a circuit flows from a point with a more positive potential to a point with a more negative potential, although the electron moves in the opposite direction.
In this case, it usually has a value for the summer position and another for the winter position. In summer, when the water heats up less, the value is lower. In winter, when the water is hotter, the power value is greater, and therefore consumption electrical energy also more.
It is measured in kWh, which means kilogram watt-hour. This kilogram equal to a kilogram, kilometer and means 000 times. A watt-hour is already a measure of electrical energy. Although this may seem strange to you. This watt-hour is a unit of energy. Remember that a watt is a unit of force and an hour is a unit of time. Thus, a watt-hour is the product of power over time and 1 kWh is 000 watt-hour. At this stage we can take some beads of light which will be discussed with the students.
Remember: voltage is always measured between two points in a circuit, current always flows through a point in a circuit or through some circuit element.
You can’t say “voltage in a resistor” - it’s ignorant. However, we often talk about voltage at some point in the circuit. In this case, they always mean the voltage between this point and the “ground,” i.e., a point in the circuit whose potential is known to everyone. You will soon get used to this method of measuring voltage.
Electric current is a quantity whose value depends on the power of the device, as well as on the voltage at which it operates. For example, a 100-watt lamp rated at 110 volts requires more electrical current when connected than one rated at 60 watts at the same voltage. This is why a 100W bulb is brighter than a 60W bulb.
There are two types of electrical current: direct current, which is supplied from batteries, and alternating current, which is supplied from power plants to homes, industries, etc. Alternating current has a value that varies within a range during operation of the same electrical device.
Voltage is created by acting on electrical charges in devices such as batteries (electrochemical reactions), generators (interaction of magnetic forces), solar cells (photovoltaic effect of photon energy), etc. We obtain current by applying voltage between the points of the circuit.
Here, perhaps, the question may arise, what exactly are voltage and current, what do they look like? In order to answer this question, it is best to use an electronic device such as an oscilloscope. It can be used to observe voltage (and sometimes current) as a function that changes over time. We will resort to readings from oscilloscopes as well as voltmeters to characterize the signals. To begin with, we advise you to look at Appendix A, in which we're talking about about the oscilloscope, and Sect. "Universal measuring instruments", printed in small print.
In this case, it refers to the characteristic of alternating electric current obtained from electricity generating installations. In Brazil, the frequency of alternating current is 60 hertz, that is, 60 cycles per second. There are countries such as Portugal and Paraguay where the frequency is 50 hertz.
Understanding a little about souls
And for the summer. In which position is the current greater?
- What energy transformation does a shower perform?
- Where is he located?
- When does the water get hot?
- The resistor is divided into two sections.
- What is the position and for the winter position?
In real circuits, we connect elements to each other using wires, metal conductors, each of which at each point has the same voltage (relative to, say, ground). In the region of high frequencies or low impedances this statement is not entirely true, and we will discuss this issue in due course. Now let’s take this assumption on faith. We mention this to make you understand that the actual circuit does not have to look like the schematic diagram because the wires can be connected in different ways.
Connections in winter and summer correspond to the same voltage, to different powers. The thickness of the wound wire - resistor - commonly called "resistance" - is the same thing. Connections in winter and summer are obtained using different lengths resistors. IN summer time used for connection most of the same wire, and the winter connection is made using a small part of the wire, in the summer position a larger section is used.
In the winter connection, the current in the resistor must be higher than in the summer position, which allows for increased power and therefore heating. When the stress, material and thickness are kept constant, we can make the following relationship according to the following table.
Remember a few things simple rules concerning current and voltage.
1. The sum of currents flowing into a point is equal to the sum of currents flowing out of it (conservation of charge). This rule is sometimes called Kirchhoff's law for currents. Engineers like to call this point in the circuit a node. A corollary follows from this rule: in a series circuit (which is a group of elements that have two ends and are connected by these ends to one another), the current at all points is the same.
If we have a lamp with a power of 100 W with a voltage of 110 V, we have power P and the same lamp with a voltage of 220 V, what is the power in this case? Below are examples of activities with students in the classroom. In these activities, students will learn how to operate a multimeter, measure voltages, currents, etc.
Materials needed: multimeter, batteries and wires. If the teacher has resistors available for use, small circuits can be set up and more content covered. Figure 2 - Insert the batteries as shown in the figure below. In this assembly we were able to measure the potential difference between two lamps.
2. When connecting elements in parallel (Fig. 1.1), the voltage on each element is the same. In other words, the sum of the voltage drops between points A and B, measured along any branch of the circuit connecting these points, is the same and equal to the voltage between points A and B. Sometimes this rule is formulated as follows: the sum of the voltage drops in any closed loop of the circuit is zero. This is Kirchhoff's law for stress.
Figure 3 - Here we will measure the potential difference of the socket. Figure 4 - Value obtained with reference to Figure 3. From the experiments, students were able to plot a graph of voltage versus current, three measurements are enough to see the behavior of the graph.
The teacher can discuss slope lines and power. Voltage, current, ohms and power. Voltage can be compared to a building, the higher the voltage in the building, the lower the latter will be, the lower the voltage. In electronics, similarity is often used in a similar way to this, simply explaining a topic that would be difficult to understand on the fly without these tricks. As you can see in the picture, each floor costs 10 volts. The first building consists of a plane, so it costs 10 V, the second consists of 4 and the third costs 3.
3. Power (work done per unit time) consumed by the circuit is determined as follows:
Let's remember how we defined voltage and current, and we find that power is equal to: (work/charge) (charge/time). If the voltage U is measured in volts and the current I is measured in amperes, then the power P will be expressed in watts. Power of 1 watt is 1 joule of work done in 1 s.
The voltages in question are for the first floor, but if other references are made, everything changes. If everything is considered by the 2nd building, the first is -30V, the second is 0 and the third is -10V. To better understand the concept, just think about how you look at the buildings in question.
If you look at building 3, you'll see the first building with 20 floors running down to -20 volts, the second building with a floor over 10 volts, and the third where you're looking at 0 volts. The more electrons pass through in a second, the greater the current flowing through the conductor. The nature of the current arises from the characteristic that two bodies have in contact, in which they try to take equal electric charge to eliminate the energy level, this shift of the electron is called "current". Current is expressed in Ampere, a name derived from its discoverer, the French physicist André-Marie Ampere.
Power is dissipated as heat (usually) or sometimes expended in mechanical work (motors), converted into radiant energy (lamps, transmitters) or stored (batteries, capacitors). During development complex system one of the main ones is the question of determining its thermal load (take, for example, computer, in which the by-product of several pages of results from solving a problem is many kilowatts of electrical energy dissipated into space in the form of heat).
This law relates voltage and current to another parameter called "resistance". This can desired to say that current is directly proportional to voltage and inversely proportional to resistance. The formula of the law and its conclusions are as follows. With these formulas derived from the ohm law, various types of problems can be solved. In the first figure, you can calculate the current circulating in a simple circuit formed by a bulb, a battery and a conductor.
The light bulb has a filament that has some resistance. This other figure shows how to obtain voltage by knowing the current and resistance of an incandescent lamp. The other still depicts how to calculate the filament resistance by knowing the battery voltage and the current circulating in the circuit.
In the future, when studying periodically changing currents and voltages, we will have to generalize a simple expression in order to determine the average value of power. In this form it is valid for determining instantaneous value power.
By the way, remember that you don’t need to call current current intensity - it’s illiterate. You also cannot call a resistor a resistance. About resistors we'll talk in the next section.
In electronics, there are components called "resistors" that have a certain amount of resistance. These can be found at electronics stores or TV recyclers, but online they can buy them anywhere or salvage them from outdated or obsolete appliances. The side figure demonstrates resistance to metals.
Siemens is named after the physicist Werner von Siemens. When using hot water from an electric water heater or cooking or heating food on an electric stove, it unknowingly uses the Joule effect, in which resistance is part of these types of appliances or users.