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# Guide for Tech Beginners - Voltage, Current, Resistance

## Voltage, Current, Resistance

These are very fundamental things of electronics and I know you are already familiar to these. Lets just recall.Every matter is made of atoms and an atom has three types of particles. Electron is one of the particle among them and is negatively charged. Charge is a property of electron and proton. Protons are positively charged. The charge of an electron is called unit charge. In a conductive material (silver, copper, gold, aluminium etc) there are lots of free electrons which move randomly. Voltage is a force or presser which forced electrons to flow or move in a particular direction. When voltage is applied into a conductor electrons start to move in a fixed direction and flow of electrons in a particular direction is called current. When electrons move in a conductor they face some friction. This friction is called resistance. Resistance oppose the free movement of electrons. So, we can say resistance reduce the current.

Voltage: Voltage is the presser which force the electrons to flow in a particular direction in a conductor. The unit of voltage is Volt and denoted by V. Battery is a good source of voltage. 3V, 3.3V, 3.7V and 5V are most common in electronic circuits and devices.

Current: Current is the flow of electrons in a particular direction. More formally, current is the rate of change of electron in a particular direction. Unit of current is Ampere and denoted by I. In electronic circuits current is in milliampere range (1 Ampere = 1000 milliampere). For example, typical current for an LED is 20mA.

Voltage is the cause and current is the result.

Resistance: Resistance is the hindrance to the flow of charge or electron. The unit of resistance is The SI unit of electrical resistance is the ohm (Ω).

There is an important relationship among these three quantity voltage, current and resistance:

V = IR or I = V / R or R = V / I

This relation is called Ohm's Law. Voltmeter, ammeter and ohm meter is used to measure voltage, current and resistance respectively.