Relay Help Please

[LyleCaldwell]

The jack is just connecting ground to the transistor for triggering the relay.  The caps are all fine, but thank you.

Ahh forgot something, that may sound stupid, but it's indeed important... It's not recommended to manage voltage current through jacks. In the jack, inevitably you will create shorts(both pole touch, because when you connect it, the tip[don't know if called like that]always touches ground.. so both poles always touch, small time, but touch..)... maybe you burnt something..(like the polarized cap)

Now that's a bigger issue i think... upto here i can help, hope it did help of something

bye bye

DAC

P.s. excuse my english

[aron]

The relay does not work outside the circuit either.

This part seems strange to me. At this point it does sound like defective relays but how could this be with 3 of them?

[QSQCaito]

This part seems strange to me. At this point it does sound like defective relays but how could this be with 3 of them?

I think there are two options, (a) fried 3 of them, (b) bad connection with the three of them...

I think that the possibility of relays(or any component) coming failed is way too low to get 3 failed ones in a row..

how have you tried them, using continuity with a DMM?

This is interesting, wanna see how it ends

Bye bye

DAC

[LyleCaldwell]

I've been testing for continuity with a DMM.  Between pins 2 and 3 it always reads 0 ohms, and between 3 and 4 it always reads Inf.  I've checked every trace on the board - everything is connected correctly with no shorts or bad solder connections.  Most telling, I measure 5vdc across the coil when the trigger connection is closed, and 0vdc when it is open.  The transistor is working.  The voltages are correct.  Every possible orientation of the diode, the relay, and the power polarity has been tried. 

All three relays came in one package - maybe this package was dropped and all three were damaged in transit.

From the datasheet I should be able to directly connect the leads from a 9v battery to pins 1 and 10 and have the relay flip, but that doesn't work either.

[QSQCaito]

I know!
maybe it's humidity...
lol, just kidding, too late in here, i think i'd rather go to sleep

bye bye

i'll check this tomorrow

DAC!

[Peter Snowberg]

You need to find two pins with a resistance between them of more than 1 ohm and less than infinity.

[LyleCaldwell]

Peter,
No such pins exist in these relays.  <g> 

[R.G.]

You know, unless the relay works outside the circuit, manually, it's not going to work inside the circuit.

Relays are very simple. When you put enough current through the coil in the right direction, the contacts close. Remove the current, they open.

You need to find two pins with a resistance between them of more than 1 ohm and less than infinity.

No such pins exist in these relays.

Then that tells you something else. A relay is a coil of wire making an electromagnet which moves a switch. If you don't have a resistance between two pins - most notably the two pins which you are driving as a coil - then there is no current in the electromagnet, and nothing moves.

As always go back to the datasheet. Identify the coil pins. Measure the resistance between the coil pins and compare your reading to the specification for that resistance to the datasheet. If the coils are open, the relay is not going to do anything.

If these all have open coils and you bought them from a reputable distributor, set them exchanged. If you bought them surplus or through ebay - well, give it a try. You might get your money back or replacements.

But be certain of the pinout, compare the parts to the datasheet.

[LyleCaldwell]

OK,

I had three bad NEC relays.  I picked up a cheap one from Radio Shack and it clicked just fine.  But three bad ones in a row!  Just my luck.

Yes, I have triple checked the NEC pinouts.  I don't think I'll be using that part again.

[R.G.]

I had three bad NEC relays.  I picked up a cheap one from Radio Shack and it clicked just fine.  But three bad ones in a row!  Just my luck.
Yes, I have triple checked the NEC pinouts.  I don't think I'll be using that part again.

NEC being the outfit that they are, I might advise you to consider that carefully. NEC does very high quality electronics. I would believe supplier or shipping abuse before low quality from NEC.

I have used hundreds of the EA series relays and never had a bad one.

Of course, neither of our anecdotal experiments are large enough to be a valid statistical sample.

[Peter Snowberg]

+1 on what RG just said.

I used a little under 200 of those EA series relays in a project and every contact tested good.

Failures do happen on the assembly line but they catch most of them before they make it out the door. Relays have lots of parts and take lots of steps to assemble.

[LyleCaldwell]

I didn't mean that as NEC makes crap parts.  I think I was just unusually unlucky this time.  Mouser is already sending three replacement relays - I'll report back in 2-3 days.

[LyleCaldwell]

Followup - the replacement NEC relays work fine.