Current Electricity Definition
What is electric current?
Electric current refers to the flow of electricity in an electronic circuit diagram, and to the amount of electricity flowing through a circuit diagram. It is measured in amperes (A). The larger the value in amperes (A), the more electricity is flowing in the circuit.
Current electricity is defined as the flow of electrons from one section of the circuit to another.
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Types of Current Electricity
There are two types of current electricity as follows:
- Direct Current (DC)
- Alternating Current (AC)
Direct Current
A current of electricity whose direction remains the same is known as a direct current. Direct current is defined by the constant flow of electrons from a region of high electron density to a region of low electron density. Direct current is used in many household appliances and applications that involve a battery.
Alternating Current
The current electricity that is bidirectional and keeps changing the direction of the charge flow is known as an alternating current circuit. The bi-directionality is caused by a sinusoidally varying current and voltage that reverse directions, creating a periodic back-and-forth motion for the current. The electrical outlets at our house and industries are supplied with alternating current.
Electric current definition
Electrical current is the flow rate of electric charge in the electric field, usually in the electrical circuit.
Using the water pipe analogy, we can visualize the electrical current as a water current that flows in a pipe.
The electrical current is measured in an Ampere (amp) unit.
Electric current calculation
Electrical current is measured by the rate of electric charge flowing in an electrical circuit:
i(t) = dQ(t) / dt
The momentary flow current is given by the derivative of the electric charge by time.
- i(t) = is the momentary current I at time t in amps (A).
- Q(t) = is the momentary electric charge in coulombs (C).
- t = is the time in seconds (s).
When the current is constant:
I = ΔQ / Δt
- I = is the current in amps (A).
- ΔQ = is the electric charge in coulombs (C), that flows at a time duration of Δt.
- Δt = is the time duration in seconds (s).
Current law Example
When 5 coulombs flow through a Resistor for duration of 10 seconds, the current will be calculated by:
I = ΔQ / Δt = 5C / 10s = 0.5A
Current direction
| Current type | from | to |
|---|---|---|
| Postitive Charges | + |
- |
| Negative Charges | - |
+ |
| Conventional direction | + |
- |
Current calculation with Ohm’s law
The current IR in amps (A) is equal to the resistor’s voltage VR in volts (V) divided by the resistance R in Ohms (Ω).
IR = VR / R
Current in series circuits connection
Current that flows through resistors in series is equal in all resistors – just like water flows through a single pipe.
ITotal = I1 =I2 = I3 =…
ITotal – the equivalent current in amps (A).
I1 = current of load 1 in amps (A).
I2 = current of load 2 in amps (A).
I3 = current of load 3 in amps (A).
Current in parallel circuits Connection
Current that flows through loads in parallel – just like water flows through parallel pipes. The total current ITotal is the sum of the parallel currents of each load:
ITotal = I1 + I2 + I3 +…
ITotal = the equivalent current in amps (A).
I1 = current of load 1 in amps (A).
I2 = current of load 2 in amps (A).
I3 = current of load 3 in amps (A).
Current divider Connection
The current division of resistors in parallel is
RT = 1 / (1/R2 + 1/R3)
or
I1 = IT × RT / (R1+RT)
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Kirchhoff’s current law (KCL) Circuit
The junction of several electrical components is called a node. The algebraic sum of currents entering a node is zero.
∑ Ik = 0
Alternating Current (AC) Circuit
An alternating current is generated by a sinusoidal voltage source.
Ohm’s Law
IZ = VZ / Z
IZ = current flow through the load measured in amperes (A)
VZ = voltage drop on the load measured in volts (V)
Z = impedance of the load measured in ohms (Ω)
Angular frequency
ω = 2π f
f = frequency measured in hertz (Hz).
ω = angular velocity measured in radians per second (rad/s)
Current measurement
A Current measurement is done by connecting the ammeter in series to the measured object, so all the measured current will flow through the Ammeter. The ammeter has very low resistance, so it almost does not affect the measured circuit Connection.
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