What is ground potential,,,what is its use??

Question

is it used as a reference point or something?? its used in the common base configuration of a BJT pnp (or npn) transistor (its connected to the base)....what is its role in the transistor???

Answer 1

It has no role in a transistor.

Transistors are not connected to Earth.

As you know they have a Base, Collector and Emitter.

Earth is only used in higher voltage devices to protect from electric shock.

The Earth is connected to the metal body of the component and if it becomes live the voltage is grounded to Earth.

The Earth is as it says, connected to the Earth (Ground).

Answer 2

Everything needs a reference point.  Height is often measured from sea level.  Pressure is measured with respect to the pressure of the atmosphere at sea level.  Water pressure is measured with respect to the force of the water at the outlet point.

Electricity is measured from a reference point often called ground.  If you could tap into a multi-cell battery, like in your car, and find the middle cell of the battery, then you would find the the positive terminal is at ~ +6v and the negative terminal at ~ -6V.  We measure it from the negative terminal in modern automobiles, which we have mechanically tied to the body of the car, and find the negative terminal to be a 0v, ground potential, and the positive terminal at +12V (13.8v, actually).

In an electronic circuit, you will find both positive and negative voltages, with respect to ground.  Without the ground reference point it would not be able to measured and have any meaning.  

Ground is simply an arbitrary point from which we measure all voltages.  It is just that simple.

Answer 3

Potential is another way of saying voltage, the potential at ground is zero therefore ground potential is zero.

In a 2 phase home power supply ground would be the neutral wire. This is the wire that the live current returns from a load through. The earth wire is a seperate item which is purely there as a safety measure.

There is often confusion between ground and earth so be careful but the ground potential is as above.