Electric Current
Electric current can be defined as the flow of charged particles. Or the flow of electrons in a conducting material is called Electric current.One of the often-used definition of current is “The rate of flow of electric charge in a specific part of a conductor during a specific duration is called is current.
Electric Current formula
As discussed above, that current is the flow of charge-carrying particles. Therefore, the first electric current formula in the term of charge may be written as.If the flow of current is variable, then the amount of current during a specific interval will be
I=dQ / dt
The symbol of current is I, while the SI unit of current is Ampere. One Ampere of current is the motion of 6.25 × 108 electron particles in one second. The unit of charge is coulomb and time is second. Therefore, the corresponding unit of current (Ampere) will be (Coulomb/Second).
Electric Current formula (According to ohm Law)
According to ohm Law, the current is related to the resistance of a conductor connected to the voltage source. The amount of current is directly proportional to the voltage applied and inversely proportional to the resistance.
I=V / R
The equation indicates that if the number of voltage increases, the current value will increase while conversely, if the value of resistance in a circuit is less the value of current will be greater Or Vice versa. The corresponding Unit of current, in this case, will be Volt divided by Resistance.
Electric Current formula (If power is available)
In some cases, if the value of power and resistance is available. We can find the value of current using the following formula
I=√(P/R)
Where “P” is the value of power and “R” is the value of resistance.we know that the unit of P is watt and the unit of R is ohm there the Ampere, in this case, will be equal to the square root of power divide by resistance.
AC loads current formula
AC loads are divided in two, single and three phases loads, The electric current formula in almost the same for both except using (√3) in case of three phase loads.
Single phase loads
Single phase loads are the loads working on one phase and neutral power source, 1 phase loads are like single phase induction motor, lighting fixtures and domestic loads.
TO calculate current for single phase loads we use the following electrical power formula:
P = V * I * cos Φ
Then I = P / (V * cosΦ)
Where
P : Electrical power in Watts
V : voltage in volt
I : current in amps
cos Φ : is the power factor of the load
Three phase loads
Three phase loads are the loads working on one three power source, 3 phase loads are like three phase induction motors and most of industrial loads.
TO calculate current for three phase loads we use the same mentioned formula but with a little change as follows:
P =√3 * V * I * cos Φ
Then I = P / (√3 *V * cosΦ)
Current calculator for 1 and 3 phases AC loads
Electrical4uonline design engineer made a simple online electrical calculator for AC loads, try it below
DC current calculation formula
Direct current is the current with direct value and magnitude, i.e no changing in direction or value like AC current, DC current source like batteries and dynamos.
Using Ohms law mentioned above we can easily calculate DC current as follows
I=V / R
I : DC current.
V : DC voltage.
R : Electrical resistance.
Direction of Current
Current flow in conductors. The reason for the flow of current is due to the motion free electron. While in ionized gases or electrolytes current flow due to the electrons (-) & positive (+) ions. Both of these move in opposite directions to each other. Therefore the direction of current will be the in which direction positive charges move. We can also say that current flows in from positive to negative. Or the direction of current is will the opposite direction in where electrons flow.
