# Circuit (newbie question)

Discussion in 'General Electronics Chat' started by NY10, Aug 12, 2010.

1. ### NY10 Thread Starter Member

Jul 30, 2010
47
0
Hi, all

How do you make a ground pin without using ground ?

For example, I am trying to build the circuit that connect to the motor. I am using circuit trainer ground at the moment, but if I actually hook up the motor to the circuit that I build, I am no longer using the circuit trainer, which means that I have to have some sort of ground.

Does anyone have inputs ?

Thanks.

Aug 6, 2010
65
1
it would help to see the circuit. what is the circuit trainer?
you should be able to just run a cable from the motor to the negative terminal (ground) of whatever supply you are using..

3. ### Wendy Moderator

Mar 24, 2008
21,012
2,744
Ground in electronics is rarely ground. It is a reference point by which all voltage levels, AC and DC, is read. It is as much a fiction and convenience as anything.

It is where you connect the other power supply lead when you want +10V, or -10V. It is where you connect the ground lead from the oscilloscope. It is where you connect the negative lead from your DVM before you start probing around.

4. ### marshallf3 Well-Known Member

Jul 26, 2010
2,358
202
The ground (negative of a circuit) is much like the water pipe leading into your house, it's where all the electrons come from.

The positive is much like the sewer pipe leading out of your house, it's where all the electrons you've used return ack to the source (eventually in this analogy) to be used again.

The pressure difference between them is the city's pumping station or water tower; it creates the potential between the two as pressure which does all the work.

What come into a house but ends up not going back out the sewer, let's just call it energy radiated in another manner such as RF.

It all sounds silly but electricity can be equated to water flow and is often easier to understand that way. Pressure = voltage. Amperage = volume. Faucets = switches or transistors. Smaller pipes or partially open faucets are resistors, anti-hammer devices or expansion tanks are capacitors.

5. ### shortbus AAC Fanatic!

Sep 30, 2009
4,540
2,576
This is another question that I have noticed coming up on the forum lately. People calling circuit ground "ground". Thinking that ground is "EARTH ground" in a circuit, when they really mean "0(zero) volts".

It took me a while to figure that out too. But the practice of calling it ground has been around so long it won't change.

6. ### gootee Senior Member

Apr 24, 2007
447
50
Yeah but "0 Volts" can also be problematical, and has to be relative to something else. Maybe "circuit common" would be OK. But ALL of them are less than desirable if they are used in schematics as some symbol that goes nowhere and implies that all "grounds" are always at the same potential, since it obfuscates the fact that HOW everything connects to the common "ground" can be important, and ground is rarely zero Volts (even relative to the rest of the circuit, except maybe at a single point, usually some distance away from where it is used as zero volts), and that different parts of circuits often should not share ground-return conductors even if they end up at the same place, etc etc.

7. ### marshallf3 Well-Known Member

Jul 26, 2010
2,358
202
At least in electrical wiring they got it right - there's a neutral and a ground despite the fact they connect at some point in the distribution circuit.