Grounding Issue

[none none]

Can the below be done safely? I have two circuits running 2 different
sources.. space is limited and if I can get away with using a single ground
that would be fantastic.

+120VAC-----------------|+ AC
-----------------| LOAD
|
GND------|
|
-----------------|-DC
+12VDC-------------------|+ LOAD

 

[Jim Thompson]

Can the below be done safely? I have two circuits running 2 different
sources.. space is limited and if I can get away with using a single ground
that would be fantastic.

+120VAC-----------------|+ AC
-----------------| LOAD
|
GND------|
|
-----------------|-DC
+12VDC-------------------|+ LOAD

I presume a bridge rectifier?

The answer is no... sparks will fly... you will be injured... don't do
it.

...Jim Thompson

 

[John Popelish]

Can the below be done safely? I have two circuits running 2 different
sources.. space is limited and if I can get away with using a single ground
that would be fantastic.

+120VAC-----------------|+ AC
-----------------| LOAD
|
GND------|
|
-----------------|-DC
+12VDC-------------------|+ LOAD

I doubt it. What voltage appears on the 12 volt output if the ground
connection goes open circuit?

 

[none none]

Here is clarification for you on what i'm actually doing.
I have a cold cathode light that runs off 120VAC, i have a inverter that
converts 12VDC to the neccessary 120VAC.. i have an series of LED's that
need DC.. so i was thinking of running the positive line for the DC power to
the LED's then just hook the ground of the LED segment to the same ground as
the return to the inverter.

 

[Richard Henry]

I doubt it. What voltage appears on the 12 volt output if the ground
connection goes open circuit?

With respect to what?

 

[John Popelish]

With respect to what?

With respect to the open circuit ground node. In other words, across
the 12 volt load.

 

[[email protected]]

Here is clarification for you on what i'm actually doing.
I have a cold cathode light that runs off 120VAC, i have a inverter that
converts 12VDC to the neccessary 120VAC.. i have an series of LED's that
need DC.. so i was thinking of running the positive line for the DC power to
the LED's then just hook the ground of the LED segment to the same ground as
the return to the inverter.

Most small inverters (cigarette lighter deals) do not have a grounded
(neutral) conductor. The center pin, typically the grounding
conductor, may connect to the inverter case but nowhere else. I
suppose you wouldn't hurt anything if you connected the inverter case
to the DC ground and used that for your DC. That would be normal if it
was installed in a car.You still would not have any connection to the
AC side.

 

[tooth]

I doubt it. What voltage appears on the 12 volt output if the ground
connection goes open circuit?

 

[tooth]

John, this circuit may or may not be done. What it really comes down to
is if there are any other parts of the circuit that come into contact
with each other.
For example.
If your just running a light from the 12v source then yeah, no problem.
On the other hand, if the high voltage section is running an audio amp
and the 12 volt end some other form of audio then it gets very complex
but I would say 99% NO.

I don't know what your tying to pair together so let me know.
If you really need to know what your doing just use your meter, the
meter doesn't lie, you just have to know how to use it.

Seperatly power up both circuits and check with a volt meter between
the grounds and see how much of a potentional difference there is.
If there is 110 or some out rageous number then Hell NO, you can't do
it.
For audio purposes you may be able to fix this problem with a simple
capacitor.
TELL ME WHAT your doing.

The tooth.
[email protected]

 

[tooth]

Sorry, I just saw your clairification.
I'm not too familliar with inverters in terms of wheather or not they
share a common ground.
Doesn't matter, they really can't simply because the ac has to be
created and you don't keep any ground in that type of circuit.
What this means is most likely your ok.
If I under stand what your doing.
The Dc end and AC ends should have nothing to do with each other.
You can always check first in both AC and DC for difference by meter
first.
I believe they are isolated thought.
This is because on the DC end you have a + and a - and with no relation
on the AC end you have a line and return.
They are two different things in this case that because of the
circuitry inbetween should be isolated and have no bering on each
other.

Alway check with MR meter first, he doesn't lie.

 

[Rich Grise]

Here is clarification for you on what i'm actually doing.
I have a cold cathode light that runs off 120VAC, i have a inverter that
converts 12VDC to the neccessary 120VAC.. i have an series of LED's that
need DC.. so i was thinking of running the positive line for the DC power to
the LED's then just hook the ground of the LED segment to the same ground as
the return to the inverter.

If the input of the inverter, and the input of the +12 regulator, come
from a single source, and the 120VAC is single-ended, then they should
almost already have a common ground.

I see no problem, as long as you can safely ground one side of the 120VAC
return.

If the grounding is done right, then the chances of it failing are almost
negligible.

Slap one together on the bench, with a bunch of fuses, and see what
happens!

Good Luck!
Rich