Ohms/Infinity

[roman90247]

Hello to all. I'm not clear on this two questions, please advise

"0" ohm reading across a switch means switched is closed? True or false

Infinity read across a switch means the switch is closed?
True or False

Please advise

[woowoo]

True
"0" is a short

false
Infinity is an open

[dhvac]

The way to think about it is that the ohm is a measurement of how hard electricity will have to travel to get across the path

For example 0 ohms would be you getting across your living room
Infinity is the same as you getting across the Atlantic with no boat

So although a “0” even though it would actually have some resistance if measured with a good meter
Would be closed
Same as a draw bridge you can’t get across it if it is open and electricity can’t get across a switch if it is open

Hope it helps and hope I didn’t insult you by over simplifying it

[Jultzya]

If you are ever in doubt, touch your leads together and see what the meter says.

[mark beiser]

Originally posted by jultzya
If you are ever in doubt, touch your leads together and see what the meter says.

It is good practice, and could save your life some day, to switch your multimeeter to ohms and touch the leads together to check continuity through them every time you use your meter.

[bornriding]

Think of a switch like a draw bridge -

When the drawbridge ( switch ) is closed - cars ( electrons ) can pass - The electrons from yur meter, for instance, passes through easily with very litle resistance - remembering that yur ohmmeter is looking for resistance - so very little resistance is close to none ( or zero )

When the drawbridge is open - no cars can pass - neither can electrons though an open switch. Bcause no current can pass, using ohms law, there must be a very high resistance between the two points of the switch. The meter sees this 'open' as a very high resistance - too high for the meter to read & WaLa, the meter shows 'infinity' or 'overload'.

Hope this helps and is not too confusing,
Richard

[gruvn]

But is this true with both AC and DC electrical circuits ?

[Edmund Forsthe]

is there a diff between ac and dc circuits

[dhvac]

yes ed there is
one starts with an "A" and the other starts with a "D"

[gruvn]

Yes, AC stands for "alternating current"

and DC stands for " direct current"

I'm glad to see that there is a lot of talk on electricity here, I did some time in class on electrical stuff. So I may be able to help you out a little if you need it.

[Edmund Forsthe]

i thought it was the circuits that was being discussed not the titles

[gruvn]

Its like this Ed if we incorporate the whole ac dc theory into the draw bridge theory, it would come out something like this, when the draw bridge closes the cars
( electrons ) can pass to the other side. Which is fine, the difference is that if the cars are in a AC electrical circuit they will be changing lanes as they cross over the bridge ( weaving ) where as in a DC circuit they will cross the bridge in a single file line.

Hope this makes it easier.

[Edmund Forsthe]

changing lanes or direction of travel

[gruvn]

Good question, on a sine wave it would like it is changing lanes but in reality it is changing directions.

[Edmund Forsthe]

now if its pulsating dc does it mean stop and go

[Swampfox]

Have your furnace checked for traffic violations

[ricm]

http://images.google.ca/imgres?imgur...lr%3D%26sa%3DN

Swamp.... Is this you?

[ricm]

Originally posted by Edmund Forsthe
now if its pulsating dc does it mean stop and go

Errr.... actually Ed, Vibrators are pulsating DC... but if you make it STOP, she GO's mad!

[bornriding]

A/c would be cars in both lanes going in different directions.
D/c would be a one lane drawbridge - traffic only goes in one direction.

And yes, this works for a/c or d/c.

LOL, Richard

[gruvn]

So AC would be traffic on the bridge right after the bars close and DC would be traffic on the bridge during rush hour.