Intermittent open circuit in 3.5mm co-ax connectors

Something else to add to the sum of human knowledge. Because I had them already , I have used 3.5mm co-axial mono connectors to join vavious bits and pieces in my P.I.R. to camera setups. In a scheme where everything depends on presence or absence of a voltage this was a Bad Move. The contact between these line-plugs and line-sockets is dodgy: a light tap at the point where they are connected is enough to interrupt the earth/shield contact. The signal part of the plug is gripped by a little spring inside the socket, and probably doesn't ever lose contact, but the outer earth/shield plug merely slides into a cylindrical hole. It looks and feels as if it is a snug fit but can, as I said, momentarily lose continuity if moved even slightly. In my scheme, such an interrupted connection is equivalent to the end of one camera trigger and the beginning of another trigger. I believe that sometimes it has occurred that there was no initial contact at all and that valid signals from the P.I.R. were never sensed by the camera. On the weekend I will replace all these connectors with RCA connectors.

Reply to
L.A.T.
Loading thread data ...

"L.A.T."

** Huh ??

Dont' kid youself, pal.

** Line sockets for jack plugs are notorioulsy unreliable, even in 6.3 mm size.
** Panel mount sockets do not suffer from the same problem nearly so much.

Trick is, there must be only *one* tip contact and it must have a strong spring action PLSU have enough travel to push hard into the notch in the tip.

This way, the shaft of the plug is offset in the barrel of the socket and makes good contact.

** Yep - RCAs are normally a tight pressure fit for both inner and outer conductors.

The plastic covers tend to disintegrate easily, so it is worth the extra to get all metal ones.

Cover them with heatshrink if touching is an issue.

..... Phil

Reply to
Phil Allison

I hate jack-plugs and sockets. I don't think I've ever had one that didn't cause trouble at some point. I'd happily see them expunged from the sum of human knowledge.

Sylvia.

Reply to
Sylvia Else

So upgrading from total s**te to slightly less s**te then :-)

MrT.

Reply to
Mr.T

**Or you could get sensible and use something decent. Provided there is ZERO chance that anyone will ever mistake them for audio connectors, you could use XLR connectors. They're tough, reliable and locking. They're also well priced. I like the Neutrik branded ones but there are others.
--
Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson

"Trevor Wilson" "L.A.T."

** Mini XLR is a possible option too.

Even DC connectors do not have the issues mini jack plugs do.

.... Phil

Reply to
Phil Allison

snip>

Makes a lot of sense. The little ones I had (Jaycar) had a double spring.

Reply to
L.A.T.

RCA connectors have the same sort of problems. Use the mini XLR type connectors from Jaycar cat nos PP1910 and PP1912 or similar.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.
Reply to
Adrian Jansen

Will they go intermittent on a very shaky table?

Background; one of my first DIY projects was a project to charge up ni- cads from a bicyle hub generator during the day to give better/ consistentbicycle lights of a night time.

Firstly I tried 6.5mm plug and socket and had flashing lights. . Next I tried RCA and same problem, but they just popped off. In the end I went to hard wired which has its own problems, mainly really water/ weather prrof switches are very expensive and hard wired didn't easily allow plug swap bypassing.

--
Great advances in Debian Linux; post a bug report and get spam in three 
days.
Reply to
terryc

I dont know for sure. But the contacts look good, and at least they are 3 of the same type of contact, not a pin and a loose fitting sleeve that relies on side pressure to make contact. Maybe that means they all fail equally :-( Full tech specs on any consumer item are almost impossible to get.

It is also possible to insert an O ring on the outer sleeve, so they can be made fairly waterproof.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.
Reply to
Adrian Jansen

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.