The definition of the concept of current strength sounds like this: these are charged particles (electrical charges) that move in a certain direction and are called electrons.
Let's imagine that a certain amount of electricity passes through a section of the chain, for example, one pendant.
It can pass in one second, or it can take an hour. Therefore, its strength is determined precisely by the amount of electricity that passes through the conductor in a specific unit of time - a second.
Content
- Current types and units
- Formulas for calculating the quantity
- Measuring with instruments
Current types and units
There are two types of current:
- Constant Is one that does not change over time.
- Variable Is the one in the outlet.
Ordinary batteries or phone batteries give out exactly the constant one. And the variable can change. When you plug a desk lamp, which does not require a lot of power into one outlet, and turn on with it, for example, a powerful vacuum cleaner, then both devices work, since the current in the network is variable, unlike the voltage, it "adjusted" to devices. If it were constant, then, depending on its value, your lamp will either burn out, or the vacuum cleaner will not work.
Measured in amperes (A) - this unit of measurement is one of the main in SI, the value is denoted by the English letter I.
Strength can be measured by the main and auxiliary units:
- Ampere (A).
- milliampere (mA) is one thousandth of an ampere.
- microampere (μA) - one millionth ampere.
If a direct current passes in a closed simple circuit, then in each place of the circuit in a second or minute its absolutely equal amount passes, since it cannot accumulate in separate areas chains. If we consider complex chains, then this rule also works, but already for individual sections of the chain, which can be considered simple.
Its quantity is measured in pendants. If exactly one coulomb passes through the cross-section of the conductor in one second, then this is one ampere. To find it, you can use special devices or formulas.
Formulas for calculating the quantity
Let's start with the formulas by which you can calculate this very force. For example, if you know how much electricity has passed through a conductor in a certain and known period of time, then you can find out its strength by the following formula: I = q / t, where:
- q is the electric charge, which is measured in coulombs;
- t - time of passage of this charge, measured in seconds.
Ohm's law reads like this: the current in the circuit is inversely proportional to the resistance and directly proportional to the voltage. This law is applied to calculate the DC current.
If you need to find a value for a variable, then the result of the formula must be divided by the root of two.
If we omit the words and go to the notation, then the formula looks like this: I = U / R. The letter I is the current strength in amperes. The letter U denotes the voltage in the circuit, which is measured in volts. The letter R stands for resistance, it is measured in ohms.
Knowing this formula, you can easily calculate the voltage or resistance in the circuit.
You can also find the following record of the law: I = U / R + r. This is a complete Ohm's Law, which, in addition to the resistance of the external elements of the circuit, takes into account the resistance inside the power supply and allows you to calculate the current consumption.
Measuring with instruments
An ammeter is a special device with which you can find out what is the current strength in the circuit. The markings on the ammeter will show you the result. It is connected to the gap in such a way that electricity flows through the device. This connection is called serial. You can connect anywhere, since the force is the same in any part of the closed circuit. This method is used to measure direct current.
If an ammeter is not at hand, then you can use a voltmeter - a device for measuring the voltage in a circuit. To do this, it must be connected in parallel to an electrical circuit. Having measured the voltage in the circuit and knowing the resistance, we can calculate the current strength using Ohm's formula.
There is also an electromagnetic method for measuring AC and DC currents. This requires a special magnet-modular sensor. He finds the desired value by analyzing the electromagnetic field.
Do not forget that current is like fire - it is useful in the same way as it is dangerous. Even one tenth of an ampere can be dangerous and even fatal to humans. But in some household appliances it can reach 10 or more amperes. Even in an ordinary incandescent light bulb, it can be enough to kill a person. Not to mention the technology somewhere in the industry, where it sometimes reaches several thousand amperes. So be careful.
