I have been researching the electron flow which goes from negative to positive in a battery. Since ground the returning point in a circuit, shouldn't ground be the positive terminal?
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5\$\begingroup\$ Ground is an arbitrary reference point you can choose wherever you want. All other potentials in the circuit are measured relative to ground. So by definition, ground is at 0 potential and it is neither positive or negative. \$\endgroup\$– The PhotonCommented Jul 25, 2015 at 15:56
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1\$\begingroup\$ Conventional current flows in the opposite direction to the flow of electrons. Mainly for historical reasons. \$\endgroup\$– Tom CarpenterCommented Jul 25, 2015 at 16:08
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1\$\begingroup\$ Positive or negative compare to what reference? But if you ask what is the charge of earth surface the answer is: it is negatively charged. \$\endgroup\$– GR TechCommented Jul 25, 2015 at 18:01
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\$\begingroup\$ For people who want to connect the PC power/reset buttons to their motherboard: It does not matter if you connect + or - to GND. Both buttons create their signal by shortcutting both pins. So it really does not matter. \$\endgroup\$– stackprotectorCommented Dec 23, 2022 at 17:39
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2 Answers
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Think of ground as the Earth beneath your feet. That's where the name comes from.
It doesn't matter to the circuit whether the most positive node or the most negative node is connected to ground - ground is simply a reference point from which all of the other voltages are measured.
Note that Ground is also much more than a reference point - it is part of Electric Power Distribution safety and is important when dealing with sensitive, low-level signals. But for the purposes of THIS discussion, let's just talk about it being the reference point.
Telecom systems world-wide use -48 Vdc (nominal) as the talk battery for their phone system. That is: the live conductor on a telephone line is sitting at about -48 Vdc if you measure it using a multimeter with the (-) lead of the meter connected to Earth ground.
The reason for choosing to use -48 Vdc is physical - there are certain electrochemical reactions that occur if a telephone conductor should have a leakage path to ground.
Similarly, old automobiles (before the mid '60s) often used a -6 Vdc battery supply: the battery (+) terminal was tied to the chassis.
Electronic convention has current flow from (+) to (-). The reasons for this are historic and even though we know now that this is incorrect, there is far too much existing infrastructure to consider changing that convention.
answered Jul 25, 2015 at 16:19
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\$\begingroup\$ Thanks for answering Dwanyne. I never understood it when they say "where voltages are measured". What does that mean exactly? \$\endgroup\$ Commented Jul 25, 2015 at 17:04
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\$\begingroup\$ Basically, what they mean is: where do you connect the negative lead from your multimeter when making voltage measurements. Lets assume that you are measuring voltages within a transistor radio. The battery (-) terminal is assumed to be ground, so you would connect the meter (-) lead to that point. Now all of the voltage readings that you get as you probe various nodes within the radio are relative to that ground connection. \$\endgroup\$ Commented Jul 25, 2015 at 17:24
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It depends on the situation you refer to.The ground in a DC battery circuit is the negative point(-).The - of the battery is the most negative because there will be located more electrons, who,as you said,flow towards the positive terminal in order to equalize the number of electrons of both points.
