"Non" polarised capacitors are you inserting them the RIGHT way round?

[Sean_Goddard]

https://www.youtube.com/watch?v=BnR_DLd1PDI

[Alexismex]

Thank Sean , a very good and instructive video , i did not know the non polarised capacitor have a polarised terminals.

[homefire]

Not much concern on the stuff most of us work on.

[Goaty]

Interesting - It gave me the idea to try it on my 3DSS coil as I was unsure about which were the start and end wires and it seems to work.

[rickb]

It is not a polarity issue. The issue is which lead is connected to the outside layer of foil for shielding purposes. The outside layer is always grounded unless you want the possibility of 50/60 hz or other AC noise in the desired signal. Nothing to do with polarity. He really should know better.

p.s. If used as a coupling cap between 2 points, the banded end should be connected to the lowest impedance point.

[dbanner]

I saw this video a while ago. Interesting. https://www.youtube.com/watch?v=BnR_DLd1PDI

[WM6]

This is old knowledge from tube radio era. Seems forgotten now.

[dbanner]

Not much concern on the stuff most of us work on.

Not so sure about that, if shielded end isn't connected to Ground or virtual ground, I wonder if this could introduce noise into circuit train? Any noise, regardless of how small, ought to be a negative.

[Goaty]

It is not a polarity issue. The issue is which lead is connected to the outside layer of foil for shielding purposes. The outside layer is always grounded unless you want the possibility of 50/60 hz or other AC noise in the desired signal. Nothing to do with polarity. He really should know better.

p.s. If used as a coupling cap between 2 points, the banded end should be connected to the lowest impedance point.

I think you are being a bit picky here - in defence of Sean he did say "Non" implying it was not strictly the right term.
Maybe he could have described it as "Un" polarised but the difference seems trivial
Also, it was good that the video pointed out that the "polarity marking" on modern capacitors was not always correct.

[dbanner]

Yes, I agree, markings differ between manufacturers. You could be caught with your pants down if you don't check before installing, especially when replacing caps in vintage tube amps. I did an overhaul of guitar tube amp some years ago, changing caps etc. It worked very well on testing, so I sent it out of shop. Now I wonder about those caps I replaced.

[rickb]

I think you are being a bit picky here

I was referring to the video, not Sean. And no, I was not being picky about the misuse of terminology.

[Goaty]

I was referring to the video, not Sean.

Thanks for clarifying that.

[Koala]

We are always looking for an extra fraction of one percent. Does it help. I don't know. Who going to be the first to build two identical board one with the shield side all inserted backward and one correct and compare

[green]

We are always looking for an extra fraction of one percent. Does it help. I don't know. Who going to be the first to build two identical board one with the shield side all inserted backward and one correct and compare

What percent increase in S/N would be required to get a detectable change in detection distance? I would guess at least 20 to 30%, maybe wrong. If a large percent of the noise was from the capacitors being reversed it should make a difference.

[Koala]

What percent increase in S/N would be required to get a detectable change in detection distance? I would guess at least 20 to 30%, maybe wrong. If a large percent of the noise was from the capacitors being reversed it should make a difference.

There is a lot of variables

Design of PCB
PI or VLF
Internal versus external noise source.
Shielded case or not.
Size and manufacture of chosen capacitor.


I know that there is variation in both the control boxes and coils. There was a Tesoro dealer that use to test each control box and pick the best then do the same with the coils.

Even with today tighter tolerances there still is a difference in performance. I have seen two Dues set up identically, same program with the same size coil. One would pick up a target in the field. The other wouldn't even give an intermittent beep, nothing.