Question for the "electrical" Guru's

[wamnram]

Without knowing what probe you have, I'll guess: Your probe is polarity sensitive, and since you said it has a digital display, when polarity is reversed it stays blank. Since it is single wire, there is no internal "switch" to allow the solid-state electronics to work on reverse polarity.

[rockfla]

Originally Posted by wamnram

Without knowing what probe you have, I'll guess: Your probe is polarity sensitive, and since you said it has a digital display, when polarity is reversed it stays blank. Since it is single wire, there is no internal "switch" to allow the solid-state electronics to work on reverse polarity.

Which takes me back to my initial question: Why does "polarity" matter??? You get 6.3V either positive ground or negative ground and Volts are Volts SO why does polarity matter??? Enough so that there is a "need" of an internal switch OR posed a different way, why does my multi meter read 6.3V when black is on negative and red is on positive and will read - 6.3V when black is to positive and red is to negative???

[wamnram]

Unfortunately, Volts are not Volts. If you reverse the polarity, you go from Positive 6.3 volts to negative 6.3 volts. This causes the current to flow in the opposite direction. (Positive current flow to negative current flow). Digital circuitry does not like that.

[wamnram]

Also, Meters and Probes come in all kinds of varieties and capabilities. Most modern "Multi-meters" have internal circuitry designed to work on either positive or negative polarity. Old Vacuum tube meters (VTVM) required you to physically turn a switch to change the probe polarity. It all depends on the capability of your probe or meter.

[rockfla]

Okay, I am not trying to be obstinate , whats the difference from a + 6.3V and a - 6.3V other than the flow SO again....why is the flow any different whether is flows positive to negative or Vice Versa??? How is one direction of flow a different flow over the other direction of flow when the outcome is the same???? It is basically a circular flow and where the two meet is the "action" why does it matter to a measuring instrument??? Is it one of those "mysteries O life" things???

[wamnram]

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Please don't feel bad about asking questions, that's how we learn. Yes, very simply put, flow is flow. We don't care if river water flows from mountain to ocean or ocean to mountain, it's still just flow. The problem is that some instruments have been designed to measure the flow in one direction only. I have to run some errands so will be gone for awhile. We can discuss more later if you wish or maybe someone else can chime in.

[JayChicago]

Originally Posted by rockfla

SO again....why is the flow any different whether is flows positive to negative or Vice Versa??? How is one direction of flow a different flow over the other direction of flow when the outcome is the same????

Which way the electrons are flowing DOES matter to some electrical devices. But I don't understand electronics enough to explain this.

On our cars, ignition coils are polarity sensitive. But just about everything else is not. How about the horns? I dunno.

I think I read that solenoids don't care how they are hooked up. I think that is strange. It's an electric magnet. Why would it not be polarity sensitive? Why would it not pull the other way?

[rockfla]

Originally Posted by JayChicago

Which way the electrons are flowing DOES matter to some electrical devices. But I don't understand electronics enough to explain this.

On our cars, ignition coils are polarity sensitive. But just about everything else is not. How about the horns? I dunno.

I think I read that solenoids don't care how they are hooked up. I think that is strange. It's an electric magnet. Why would it not be polarity sensitive? Why would it not pull the other way?

Jay
You are on my same thought path as IF polarity matters, then why not to light bulbs, starters??

IF it polarity can flow two ways THEN why not make all electronic test devices work both ways???

It's the whole VHS Beta argument it seems!!!!