I'm stumped! Help! - Page 1
Forum section: electronics / general

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:15:38 pm
content: This may be a stupid request to some, but what the hell is this? I was sorting a box of spare parts I received from someone and came across several of these. They do not seem to have any resistance, don't respond to light or heat, have no capacitance but have a Red and Black wire which indicates possible polarity???Help!!!, not critical but curious...

author: Alana
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:27:18 pm
content: Colour and that trace on dark side may suggest its some sort of photocell. Try to mesure voltage while its lit and while its dark.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:29:48 pm
content: Quote from: Alana on December 20, 2013, 06:27:18 pmI thought it might well be also, but there was no resistance. It was essentially and open circuit. Tried light, dark, etc...

author: BravoV
author_rank: Super Contributor
timestamp: December 20, 2013, 06:34:06 pm
content: Set your meter to Volt or mV mode instead of resistance mode.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:41:33 pm
content: Quote from: BravoV on December 20, 2013, 06:34:06 pmTried that, nothing. But gave it a go again, and I get nothing but a few uV of random noise. No change to thermal, light, etc.

author: kxenos
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:50:39 pm
content: They are probably peltier plates. It makes a voltage differential, into a temperature one and vice-versa

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 06:59:03 pm
content: Quote from: kxenos on December 20, 2013, 06:50:39 pmAhh yes, a possibility... I can test them for this. Cool, thanks!

author: liquibyte
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:07:20 pm
content: I have a peltier and I don't think that's what this is. Maybe a flex / pressure sensor?

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:11:17 pm
content: Just tried the temp dif, another fail!Placed about -10 on the one side and heat on the other and no change.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:13:26 pm
content: Quote from: liquibyte on December 20, 2013, 07:07:20 pmI'll look into that also. I can't believe I am spending so much time on these, I guess it's just the mystery!

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:17:12 pm
content: Not a flex or pressure either. Damn, oh well.

author: jolshefsky
author_rank: Regular Contributor
timestamp: December 20, 2013, 07:23:19 pm
content: I'm going with the safe bet: "broken".It looks a lot like an old solar cell to me, but that doesn't mean much.If you flex it, does it make a voltage? Then it might be a piezo element...

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:25:38 pm
content: Quote from: jolshefsky on December 20, 2013, 07:23:19 pmFlexing does nothing. I am thinking "Broken" too!

author: SeanB
author_rank: Super Contributor
timestamp: December 20, 2013, 07:41:53 pm
content: You might need a lot of light on it, like direct sunlight while measuring both resistance and voltage to see if it is a photocell. Some are pretty poor at operating unless they are illuminated by noon sun.Edit, what you might have there is a single cell emergency battery, try dipping it in a salt solution, a teaspoon of salt in a glass of cold water and dip the cell in it and it should generate about 1V or so at around 1mA, enough to operate a clock mech or charge a capacitor to run a flasher. Clue is an expiry date of 2022..

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 07:46:57 pm
content: Quote from: SeanB on December 20, 2013, 07:41:53 pmYeah, I tried it directly with my 3k lumen torch and got no response. Unfortunately, the weather sucks here right now, and we have noooo sun! I'm starting to lose interest, I have to decide when to just throw in the towel since they were free!

author: Jon86
author_rank: Frequent Contributor
timestamp: December 20, 2013, 09:03:56 pm
content: Maybe a piezo, try hitting it quite hard?It could be anything really, probably some weird custom part for a specific product. Where did you find it?

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 20, 2013, 09:09:19 pm
content: Quote from: Jon86 on December 20, 2013, 09:03:56 pmI was given a large box of misc components, and these were found. I never seen anything quite like these before, and I have seen thousands of components in my time.

author: Rick Law
author_rank: Super Contributor
timestamp: December 21, 2013, 05:12:35 am
content: Quote from: Terabyte2007 on December 20, 2013, 06:15:38 pmYikes! Looks like an NSA listening device to me...Have you said anything "interesting" near it? .......... What? You said THAT! ......... Get your financial records ready; Watch for letters from the IRS; an audit is coming...Sorry, couldn't resist...

author: Stonent
author_rank: Super Contributor
timestamp: December 21, 2013, 05:27:28 am
content: I almost want to say some kind of antenna for something where they're not worried about distance or bandwidth.Or some kind of capacitive touch strip.

author: SeanB
author_rank: Super Contributor
timestamp: December 21, 2013, 06:25:01 am
content: Try dipping it in a salt solution. I thought later and edited to say it might be a battery, seeing as it has an expiry date in the region of 2022.

author: TheBay
author_rank: Unknown
timestamp: December 21, 2013, 10:22:05 am
content: Some form of moisture sensor?

author: Skimask
author_rank: Super Contributor
timestamp: December 21, 2013, 11:20:13 am
content: I was going to say fluorescent light is practically useless on solar panels.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 21, 2013, 12:16:24 pm
content: Quote from: Rick Law on December 21, 2013, 05:12:35 am

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 21, 2013, 12:37:41 pm
content: This is certainly a mystery. I can usually identify a device using all my test gear within a very short time, but this one eludes me! After thinking a bit about it last night, here are my thoughts:- Aluminum Plate (Negative or Black Wire, Possibly a ground plane)- Small conductor strip with solder mask or epoxy coating of some sort. (Red wire tied to small conductive strip isolated from the metal plate, Antenna of some sort?)- No Voltage- No Current- Not Light Sensative- Not Temp, Flex or Vibration sensitive.I am thinking Antenna. Without doing the exact calculations, the length would probably place it in the 3-5GHz range depending on 1/4, 1/2 or full wave. This is my last experiment today with this hopeless little device. I am going to check it with my BK FC on the 50OHm input and see if it has any resonant response. It may, just because it is a crude exposed wire with a ground plane which may not prove anything, but the curiosity has got the best of me on this one.

author: SArepairman
author_rank: Frequent Contributor
timestamp: December 21, 2013, 01:24:30 pm
content: salt solutionormeasure capacitance change? it could be a sensor which outputs capacitance.or use a electrometer. it might be gigaohms.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 25, 2013, 07:09:48 am
content: Perhaps an electro-luminescent panel? Backlighting for an LCD?Try applying an AC signal to it. Not sure what voltage. Maybe vary up to 30V?Anyone recall what luminescent panels require?Of course, after bending it, hitting it hard and dipping in salt water, whatever it was it's probably f*cked now.Perhaps you should try heating it in a flame just to make sure.

author: VK5RC
author_rank: Unknown
timestamp: December 25, 2013, 07:16:30 am
content: I would tend to punt for a broken solar cell, the colour of the plate and I think the polarity of the wiring would fit.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 25, 2013, 12:44:57 pm
content: The verdict is in! I found a defect in each of the plates on the negative pad (Must have been plates that were rejected), fixed each one and bingo! They are solar cells! They appear to be single cells all producing about .5 volts each under my LED work light. I have never seen single cells like this before and I am not sure as to the production age but now I have them fixed, they could come in handy someday.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 25, 2013, 12:50:06 pm
content: Quote from: TerraHertz on December 25, 2013, 07:09:48 amLove your quasi facetious reply!