Grounding in electronics

O aterramento é confuso. Eu acho que a maioria das pessoas que começaram eletrônica aprendizagem pediram «O que é chão?» Em um ponto ou outro. Você está realmente supor para ligar o circuito para a terra? Eu acho que o chão razão é confuso, é porque é diferente em eletrônica e em sistemas elétricos de alta tensão.

Grounding in electronics

I got an email from a reader a little while back:

«[...] The ground symbol keeps appearing at different points in a circuit and I could not understand why a particular location was chosen for grounding [...]»

And here is what I wrote back:

Usually in electronics, ground is just a name we give to a certain point in the circuit. In a circuit with one battery (with a positive and a negative terminal), we usually refer to the negative terminal as ground.

Flow of Current When the Ground Symbol is Shown

To see how the current flows in a circuit diagram with ground symbols, just connect all the points that have ground symbols. That is what you do when you build the circuit.

A schematic using ground symbols

The same schematic shown without ground symbols

Circuits With Positive, Negative and Ground Connections

In some schematic diagrams you will find a connection to a positive terminal, a negative terminal, and a ground terminal. This is common in for example amplifier circuits. So, how does this work?

In this scenario, the ground is the middle-point between the positive and the negative terminal. If the voltage measured between the negative and the positive terminal is 9 volts, this means the ground would be at 4.5 volts. But in this case, we would call the positive terminal 4.5 volt and the negative terminal -4.5 volts. And the ground terminal we would refer to as 0 volt.

If you’re confused by how we can just say that the positive terminal is now 4.5 volts and so on – then let me remind you that voltage is a measurement between two points. So by calling the negative terminal -4.5 volts and the positive 4.5 volts, we still have 9 volts difference between them.

If you wonder how you can power such a circuit – just connect two power sources, like this:

What is Ground in High-voltage Systems?

Sometimes though, the «ground» term refers to an actual connection to the ground/earth. But that is usually when talking about high-voltage systems.

That’s not my field, but for the curious ones – read more here:http://en.wikipedia.org/wiki/Ground_(electricity) Via