With the introduction of electrical systems such as solar panel systems into people’s lives, more and more people are beginning to realize that in today’s day and age, understanding the basics about electrical systems is a must for maintaining a normal household life. As a result, many of the basics of electrical systems include the meanings of the units of measurement of various common physical quantities and the conversions between different units of measurement. In this article, we will introduce you to several common units of measurement for physical quantities in electrical circuits, the ampere, the volt, and how to convert between the two.
An ampere is a unit of current (I) in an electrical circuit, abbreviated as amperes and symbolized as A. It is commonly used to describe the amount of current in a circuit. From a microscopic point of view, it expresses the amount of charge that passes through a section of a circuit in an instant, i.e., the speed at which the current passes through a section.
The volt is the unit of voltage in an electrical circuit, abbreviated as volt and symbolized as V. It is often used to describe the number of charges passing through a section of a circuit at the same time, and can therefore be used to indicate the amount of “power” of the current in the circuit. The greater the value of the volt in a circuit, the greater the force of the current in that circuit, and conversely, the smaller the value of the volt, the less the force of the current in that circuit.
In addition, the volt can be a unit of potential energy. The volt can also be used as a measure of the amount of energy difference between a unit of electrons in an electric field due to the difference in potentials at their locations, with a numerical magnitude equal to the amount of work required to move a unit of positive charge from one end of the potential difference to the other end due to the electric field force. When the volt is used as a unit of potential energy, its value decreases, indicating that the electric field force is doing positive work in moving the charge. Its value increases, indicating that the electric field force does negative work in the process of charge movement.
An ohm is the unit of resistance of a component in a circuit, abbreviated as ohm and symbolized as Ω. It is often used to describe the ability of a circuit component to block the passage of current. The source of its calculation is:
1Ω = 1V ÷ 1A
That is to say, a section of the circuit voltage of 1V, and the current through the 1A, the resistance value of the section is 1Ω.
Watt is the unit of power of electrical appliances, but also one of the most widely used units of electrical physical quantities, usually used to describe an electrical appliance in the completion of some kind of work in the degree of energy consumed. It is defined by the formula:
P (W) = V (v) × I (A)
That is to say a section of the operating voltage of 1V, the operating current of 1A appliances, its power is 1W.
First of all, we need to know that Ampere and Volt do not belong to the same unit of measurement of physical quantities, so in the conversion from Ampere to Volt, it is not possible to convert directly through the multiplier relationship in the International System of Units (SI). In order to convert between the two, we need to introduce intermediate physical quantities. It is worth noting that the intermediate physical quantities are different for different conversion methods, and the conversion formulas are categorized into the following two main types.
Introducing the watt as the unit of measurement of the intermediate physical quantity (power):
V (v) = P (W) / I (A)
As well as, introducing the ohm as the unit of measurement for the intermediate physical quantity (resistance):
V (v) = I (A) × R (Ω)
In order to help you better understand and master the above formula, the following will take a 200W solar panel system as an example, assuming that its operating current is 1.6A, then its operating voltage is 200W ÷ 1.6A = 125v.0
Or an electrical system is known to operate within the current of 1.5A, the internal resistance of 300Ω, then the operating voltage is
1.5A × 300Ω = 450v.
