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ELECTRIC CURRENT :explode: lightning-strike-in-kuala-lumpur - Coggle…
ELECTRIC CURRENT :explode: 
An electric current is a flow of electric charge in a circuit. More specifically, the electric current is the rate of charge flow past a given point in an electric circuit. The charge can be negatively charged electrons or positive charge carriers including protons, positive ions or holes.
What is direct current, DC? :no_entry:
A simple DC circuit is shown in the figure below which contains a DC source (battery), a load lamp, a switch, connecting leads, and measuring instruments like ammeter and voltmeter.The load resistor is connected in series, parallel or series-parallel combination as per requirement.
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Types of DC Circuit
The DC electric circuit is mainly classified into three groups. They are the series DC circuit, parallel DC circuit, and series and parallel DC circuit.
DC Series Circuit
The circuit in which have DC series source, and the number of resistors are connected end to end so that same current flow through them is called a DC series circuit. The figure below shows the simple series circuit. In the series circuit the resistor R1, R2, and R3 are connected in series across a supply voltage of V volts. The same current I is flowing through all the three resistors
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DC Parallel Circuit
The circuit which have DC source and one end of all the resistors is joined to a common point and other end are also joined to another common point so that current flows through them is called a DC parallel circuit.
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DC Series-Parallel Circuit
The circuit in which series and parallel circuit are connected in series is called a series parallel circuit.The figure below show the series-parallel circuit. In this circuit, two resistor R1 and R2 are connected in parallel with each other across terminal AB. The other three resistors R3, R4 and R6 are connected in parallel with each other across terminal BC.
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Resistance :warning:
Resistance is the hindrance to the flow of electrons in material. While a potential difference across the conductor encourages the flow of electrons, resistance discourages it. The rate at which charge flows between two terminals is a combination of these two factors.
In a simple circuit comprising of a battery or voltage source and a resistor, then assuming the connecting wires have no resistance, then the higher the resistance the less the current that will flow.
What are resistors?
In order that the current can be limited in a particular circuit, a component known as a resistor may be used. Resistors come in a variety of forms from large wired components, or even some using terminals to the very small surface mount components used in many electronics circuits today.
Ohm's Law :warning:
Ohm's Law states that the current flowing in a circuit is directly proportional to the applied potential difference and inversely proportional to the resistance in the circuit.
In other words by doubling the voltage across a circuit the current will also double. However if the resistance is doubled the current will fall by half.
In this mathematical relationship the unit of resistance is measured in Ohms.
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Resistivity :warning:
The resistivity of a substance is the resistance of a cube of that substance having edges of unit length, with the understanding that the current flows normal to opposite faces and is distributed uniformly over them.
The electrical resistivity is the electrical resistance per unit length and per unit of cross-sectional area at a specified temperature.
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Electric power :warning:
Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. It is the rate of doing work.
The unit of power is the watt which is denoted by the symbol W and it is named after the Scottish engineer James Watt (1736–1819).
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