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Electricity is one of the major power sources today. We use it for everyday purposes, like lighting the bulb, powering the motor, watching TV etc. Simply, electricity can be considered as a flow of electrons.When we are talking electricity, it has two things which are called positive and negative.
There are two types of electricity-

Alternating current(AC) – A Different is AC change its polarity( positive(+) and negative(-) )direction each time. Great example is main electricity.Main electricity(110-240V AC 50/60Hz), it means is , change positive and negative direction 50 or 60 times.
Direct current(DC) – DC never change it polarity. Best example for DC is a battery. It doesn’t change polarity(+,-).
Electricity power can only flow with conductors. Insulators can’t carry electricity. Thus, for safety reasons, we can use insulators.
If we take wire, as an example, inside it, you can see copper-like conductors while around it cover with insulators like rubber. So it will save us from electric shock.
Electricity itself can be divided into the three main parts:
Voltage (V), Current (A), and Resistance (R), and all together we can call it power.

Voltage (V) – Which can cause to flow electrons.
Current- Simply, the flow of electrons.
Resistance – Which can be resist to that flow of electrons.
Imagine if there is a tank with pipe. I f you get water from tank because the pressure of tank (up to down or using motor). That’s much like voltage.
The water which come out of pipe like the current. If you use tap on that pipe water can reduce because it resist the water flow which similar to resistance.
e.g-
Simple circuit
If we take the battery, it has voltage and current. If we take a bulb and wire it has resistance.
Now we connect the batteries to the bulb. It will cause the bulb to light, and it consumes some power. It can also be called a closed circuit. Current can only go through closed circuits. Now, if we remove one wire, then it will not light, and it can be called an open circuit. For this purpose, if we use a switch, we can connect or disconnect the bulb. It can be used on and off the bulb.
Safety and electricity – When we use a small voltage or battery like 6v, 9v, 12v, it is really safe to use. However, when we work with high voltage and current without knowing properly, it can be really dangerous to either circuits or us. So playing with 110,240V AC or more is really dangerous and can be fatal. So you should never be touched by unknown wires, terminals etc.