whats the difference between 1 terminal power and 2 terminal power in falstad?

dragon

Oct 31, 2022
248
So, in falstad you get 2 terminal power, but u also get 1 terminal power, which is the positive without the negative and vice versa.

Whats the difference?

Delta Prime

Jul 29, 2020
2,214
They do have other applets that look like fun.

Martaine2005

May 12, 2015
4,969
One has one terminal power and the other has two

dragon

Oct 31, 2022
248
Yes but how do you use it - whats the difference of use, its obviously a different kettle of fish.

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,799
its obviously a different kettle of fish.
Not really.

Obviously the 1 terminal power supply implicitly assumes that the other end (not shown 2nd terminal) is tied to GND (0 V).
Every power supply needs two terminals. Sometimes, as is the case here, one terminal, the reference potential, is not shown to simplify the schematic.

See this example:

versus this example (voltage source also set to 5 V):

dragon

Oct 31, 2022
248
Thanks for the help.

It doesn't need a ground to operate, you can send it to a negative 5 as well if you want.

How do you actually implement it in a real circuit? Doesn't a positive always come with a negative?

Bluejets

Oct 5, 2014
7,095
It doesn't need a ground to operate
In the real world where most of us reside, a circuit requires at a minimum, 2 conductors to complete.
In nearly all instances, one is tied to the chassis.

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,799
It doesn't need a ground to operate, you can send it to a negative 5 as well if you want.
No, it does require ground.
Ground is the reference potential (0V) for the simulator. Even if you don't see it in the schematic. That's because voltages alöways, always, always are between two points. A single point can't have a voltage.
In any real circuit (which you never bothered to build and show us) you will have voltage sources with two terminals. Always.

dragon

Oct 31, 2022
248
So you showed me two ways to do it, there is one as a circuit, and other way which is just a line that ends at ground.

The one as a circuit, seems to have no current going to the ground there, it looks like a dead wire.

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,799
The one as a circuit, seems to have no current going to the ground there, it looks like a dead wire.
Right. For current to "flow" it requires a closed loop. There is no loop from the lower right connection point (post #5, second picture) to gnd.

In Falstad you can draw the circuit like this, too:

Falstad obviously inserts an implicit gnd (or 0 V reference point) to do the math for the simulation. Other simulators like SPICE require an explicit definition of the ground potential.

dragon

Oct 31, 2022
248
Ok got it, thanks for the help.

So with the +5v and the ground, how do you implement that in a real life circuit?

Bluejets

Oct 5, 2014
7,095
As in #10 above....

dragon

Oct 31, 2022
248
you cant just conduct to a chassis of a machine with half a battery on it???

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,799
Why half a battery? Where's the other half? #10 shows a complete battery.

dragon

Oct 31, 2022
248
I mean in #5, with the +5 volts and ground, is that setupable in real life??
you cant have +5 volts without -5 volts!

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,799
you cant have +5 volts without -5 volts!
Yes we can. +5 V is the positive pole, 0V (ground) is the opposite pole.
is that setupable in real life??
Of course it is. Read what I wrote:
Ground is the reference potential (0V) for the simulator. Even if you don't see it in the schematic.
Ground is only not shown in the simulator's schematic, it is implicitly assumed to be present. In real life you need to make a physical connection as shown in post #10.

dragon

Oct 31, 2022
248
I still dont understand.

Can you please demonstrate me an example of using +5v and ground in real life?? I'm totally confused about it.

Bluejets

Oct 5, 2014
7,095
I still dont understand.

Can you please demonstrate me an example of using +5v and ground in real life?? I'm totally confused about it.
I think it's time you gave some serious thought to taking up fishing or playing bowls as you just seem completely unable to grasp even the simplist basics.

Martaine2005

May 12, 2015
4,969
+5V and -5V will have a Peak to peak of 10V.
+5V and 0V will give you 5V.
The GND symbol (use your imagination) is the GND or Negative connection to the battery or power supply. It keeps the schematic tidy. It’s an invisible connection!. BUT (use your imagination) IS connected.

Martin

dragon

Oct 31, 2022
248
I think there is a trick to this tho, its definitely different to 2 terminal power, it seems to behave in a different fashion.

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