Inside a diamond tester. (thermal conductivity) 

I love it when he gets surprised and excited seeing things he did not expect.

So looks like it has two back-to-back thermocouples, so at a constant temp the voltages will cancel out. The output will be in the microvolts range, so the pot will be to cancel out the input offset & drift of the amplifier stage - there will also be some thermocouple effects on the PCB & components so it would be pretty hard to make something like this without a manual offset adjustment.

Clive is the REAL diamond!!

Clive, at times I wonder if you're self-aware of the calming quality of your voice and your channel. Given how gingerly you removed the tester from the package I think you are.

Any metal can be used as a "thermocouple" if you don't care about the actual temperature. As in this case, the rate of temperature change from one end of the rod to the other is all we are concerned with. The principal of the thermocouple relies on the material(s) Seebeck coefficient. Not an expert on this, but basically any metal develops a voltage difference from one end to the other due to the temperature difference. In a true thermocouple two different known materials are used (usually with Seebeck coefficients of opposite polarities - so the generated voltage at the ends is maximized). In this case, since we don't really care about accuracy or the actual temperature, you can get by with one rod (the wire makes up the second leg of the thermocouple in this case) and the device just registers the change in voltage (or the rate of change) due to the temperature difference along its length. As long as the wire and the rod have different Seebeck coefficients the temperature change will cause a voltage change. That's my theory anyway.

IMO. Diamonds have more industrial appeal than aesthetic.

A simple method is to hold the stone to your lip. If it feels cold like metal, then it is likely to be a diamond. Other gemstones feel warm as they are not highly thermally conductive. The synthetic gem he mentions "moissanite" has a lower density, a higher refractive index and a slightly lower hardness than diamond. However, moissanite is electrically conductive while diamond is an excellent insulator. I'm sure Big Clive could whisk up a suitable detector for it!

When I saw the ring, I thought you had John McCririck as a guest star!

I watch a lot of reviews on RU-vid to hear about how bad something is. But I really enjoy it when Clive finds something that he likes.

Don't you hate it when just at the moment you decide to go to bed, you get an notification for a new bigclive video ? :-D

My mate designed this and the Chinese brought him out.I have one and he said they stuffed it up, he still has the one that you calibrate ..The metal channel shows the different caret size and how to set it ..He is 91 now and is still as sharp as a tac..

Sounds to me that it might work like a hot-wire anemometer for measuring air speeds. The thermocouples control the current flowing through the wire to maintain some temperature. By measuring the change in current to maintain that temperature you can estimate the thermal conductivity of whatever material you touch the tip to.

I have one because I by scrap silver and other jewelry, very useful for a cheap tester, little tricky to et a hang of but once you do you can check dozens of similar sized stones really quickly once everything is set.

Could be a "Type T" thermocouple. If true, the wires are just plain copper and the rod is constantan. The two junctions would generate about 43µV per °C temperature difference...

At (5:35): Aluminium oxide is a actually a good thermal conductor. Treating the aluminium (anodizing) makes the surface quite porous and hard. For aluminium to air conductivity that might even be a plus due to the larger surface. I’d assume that the tip of the tool can’t get a good conductivity with the anodized material as it it quite hard and porous. Bare aluminium is quite malleable and might form a nicer surface and hence better conductivity. There will be a thin oxide layer on these patches too, but I thickness and porosity might be significantly less.

Should test it out on the crown

Would you mind trying that gizmo on some metals? I wonder if it can be used to differentiate between aluminum and pot/zinc metals or help classify bronze/brass alloys either directly or watching the 'swing' of the meter. A quick non-destructive method to classify metals or alloys would make picking the right weld/braze method or filler a lot easier.

Interesting on how much work has gone into designing and manufacturing for less than a £10

Always a joy to see a new Bigclivedotcom video....just a wee bit of disappointment when he doesn't have a chance to say, "fresh, juicy, lead-based solder." Still, fun to watch and I learn stuff.

The solution of course is to consciously wear moissanite instead of diamond. Why overpay when the moissanite is sparklier anyway?

Always wanted to see the inside of one of these!

The two thermocouples are the same basic idea as a "Mass flow meter" the basis for "Mass flow controllers" (feedback to control a valve position to control flow). The ptc being a heat source instead of a hot wire being cooled and temp being measured up and down wind. Cute design. Tootles... Wade

Diamond prices are highly inflated by De Beers. Ask any Geologist you know... In fact most Geologists hates diamonds to the point most of them don't even use them in their wedding rings.

Could be useful as a "Heatsink Tester"! I could always test this on the Wife's ear-rings (which are "the Real Deal") . . . . .

damn moisanites are pretty awesome actually ... the colors they make when you shine a bright light on are simply stunning

2:35 The manual says " Diamond Selecter II" but the device itself says " Diamond Selector II." So which is it?

I’ve seen black light (UV) used to tell if diamonds are real as well.

Clive, have you seen the febreze alternating dual scent air fresheners? Looking through the vents, there’s a circuit board inside with two large resistors and a capacitor. Wonder what’s doing the timing. The assembly is heat staked shut.

Wow Clive your ring has more sparkle than liberaces

Is it as good as Diamonique Diamonds, I wonder if you rubbed some Artic Silver on to that micro-controller and rub it off and see if the numbers appear so you can ID that micro-controller.

I just bought tester at amazon came with battery 9v and lasted 3 days now i have to go by a pack of 9v of duracell or energizer batteries

I would say the hardness scale you mentioned is for scratch resistance. I read that the glass of my watch has a resistance of 9 (sapphire glass) and it is probably not nearly as hard as diamond.

There are viral videos going around where people go to malls and other public places and challenge people to test their jewelry to see if it's real diamonds. Occasionally the host will adjust the dial a bit and I think he's upping the sensitivity when he thinks the person is confident and doesn't want to make them mad. It also obviously has the issue of not being able to test for moissanite.

That bass boost makes you sound like the love child of Brian Blessed and Sean Connery.

Cheers Clive, diamonds should be only used for abrasives.

Cool Beans. I was thinking they used Electrical Conductivity. Thermo Couple generate Current not so much voltage variations. They're measuring the current variance. Bet the Op AMP is set up in a Differential configuration ?

There's a make-on-demand engagement jewellery store in western Canada (Spence Diamonds in Edmonton, Alberta to be specific) selling synthetic, gem-quality diamonds in their custom engagement rings. Of course, they're still trying to market them as "Artisan Created Diamonds" and play up their 'rarest diamonds in the world' status (they have exclusivity contracts with their supplier, I think). They also insist that they're "the same cut, colour, clarity, and price" as a natural diamond, "just 20% bigger" (which is a silly way of hiding the price difference), and back them with an exchange policy for (smaller) natural diamonds. Marketing at its finest, and I've got to wonder how much their markups are. Still, even though moissanite obsoleted diamond for jewellery, I'm excited for the time when synthetic diamond gets cheap enough and large enough for useful consumer products (heatsinks, lenses, etc.). And of course the death of DeBeers, if of course those scumbags don't pivot to another scam.

Zirconium encrusted tweezers....thinking of you Uncle Frank(Zappa)💎💎💎💎💎👍

A Real Diamond Will Cut Glass... So... Is This Device Really That Affective? 1. Cut 2. Color 3. Carrot Weight 4. Clarity Can This Devise Rate The Purity Of The Diamond According To The 4 C's? Blessings: James...

Was the move "Lock Stock and 2 Loaded Barrels" or "Snatched"?

Instead of using the thermocouple effect, maybe they're measuring the resistance of the sampling rod. The PTC has a power and ground side. The ground of the PTC is used as the common for measuring the resistance at the ends. It doesn't have to be absolutely precise but would need to have both ends balanced like a wheatstone bridge. Easy job for an op-amp and eliminates the non-measuring connections from forming an accidental thermocouple.

So this thing works almost exactly like a Mass Air Flow sensor in a car intake, except instead of pressing the tip against a gemstone the tip is in the intake air stream and the other end is protected from airflow. Higher air pressure cools it faster, more airflow cools it faster, and the ECU can accurately calculate, from that, the absolute amount of air going into the engine at a given time.

Could be 2 type T thermocouples... that would kinda work with the colour code too. The white lead would be Constantan (copper nickel alloy) and the other lead would be copper. It is also a fairly low range type of thermocouple so that would increase the accuracy of the device.

Love how the calibration dial is also the volume dial 😅

The simplest answer is usually the solution - especially when you're talking cheap stuff. Constant current supplied by the two copper wires heats the rod to a set temperature. Thermistor in the middle detects temp, and dial sets it to the middle. Constant current means constant temp for set resistance in a set environment. You zero the graph, and anything you touch the tip to drops the temperature, moving the graph. Just a guess, but I find it hard to believe they'd have balanced thermocouples at that price.

So what you really have is a thermal conduction tester for your heat sink. Q&D (quick and dirty ) for R & D!

They should include a real diamond to calibrate it on. :-)

that mic bass boom makes u sound like bloody barry white

The heatsink thing and the anodization is fascinating.

that may come in handy when prospecting for gold as there has been diamonds found in the area, wonder if it works on uncut diamonds

Transistor thing? Come on, let us call it to-92 package...

I'd like to test some desktop thermal compound called IC Diamond which I believe may have diamond powder in for heat conduction between the CPU and heatsink

I suspect the chip just drives the bar graph and the clever bit is just a wheatstone bridge

How does it detect when you are touching metal? That triangle plate on the cover doesn't seem to be connected to anything. It looks like it should be connected via a spring on to the PCB through the round hole in the plastic but I didn't see any contact pads or springs on the board.

I really like the 'out-loud' thinking.

I'd be interested to see if you got a different reading on a heatsink with thermal paste. The reason anodising is beneficial to heatsinks is because it creates a microscopically porous layer which effectively increases the surface area, and hence improves dissipation. However because the surface is less smooth, it has less area in contact with the heat source. Thermal paste increases this area by filling the pores in the anodised surface, which improves thermal conductivity, so I'm guessing we'd see a bit of a difference using this on a heatsink with thermal paste.

How do the dilithium crystals stayed cooled?? Oh, they dont. That's intuguing . Awesome dude.

Why didnt you test it on a diamond?

3 of each color led? Just how much did you have to drink before making this??? There are 4 of each color led

personally maybe the op amp is use to GAIN the signal as the differential of thermal conductivity is so LOW, that the micro controller attached now can read the signal and have a range of frequencies(1-3 now have 1-100)(micro controller probably) at set up as a pontentiometer( were you can adjust a starting point[calibration]) at that given value, you set the micrometer to reals required voltage to the graphical display hence the manual calibration. to find their"zero poiint"....fr i work with thermoucple all day at work..i thought it would have been a lux sensor in that thing :L

I don't buy the 37°C of the tip. Your camera caught a larger area than just the tip and read an average. I had such devices in my hands (professional ones) and, nosy as I am, tried the temperature on the outside of my thumb or hand - it hurt a lot! You shouldn't use these for diamonds smaller than indicated in the description and shall not use it as the only indication method!

It's Pete's ring from Gavin and Stacey! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-IcvyV5iM0IA.html (skip to 3.00)

Time for a long mining session to find those diamonds

If you need a machine to tell the difference, why bother with diamonds for jewellery?

also...be careful not to "touch cloth" !!!

Thanks to you, taking apart fake SNES chips came across my first um I believe it says Nintendo on the chip but they've marred the surface quite good.. This was for a fake copy of TMNT IV Turtles in Time (banggood) usually it's some other chip. But using a Nintendo chip? Why scratch off the name? Motorola and Sony just fine but Nintendo , that SNES has 2 chips. The big one which I assume the program resides on and this smaller chip which for whatever reason has maybe 1991 Nintendo on it.

That’s why these are normally sold in pairs with the moissanite detector that looks identical but tests for electrical conductivity rather than heat....

Since the tip also generated heat, is it possible that the two copper wires are used to pass a mild current through the rod and thus heat it to 36.3C? The thermistor would then monitor rate of thermal conduction out of the rod. Possible?

Jewelry isn't supposed to sparkle. That is the easiest way to tell if it's fake. Silver, gold, diamonds, not one is supposed to be "glittery" in anyway/

ice

Artificily grown dimons don't require slave labour to create. Thus they are better for the world.

hahah this is more finnicky than politics... i suppose it's basically what you said "it's just another tool on the arsenal..."

In reality, they make great door stops

What kind of battery is that mine didn’t come with a battery

I love the joy and excitement when he finds the PTC.

The anodiding judt looks pretty. Doesnt help.

Uses thermal imaging camera to test thermal probe...why not cycle metal simple..eg ring.. and watch how GEM follows metal ...? Assuming stone large enough to see on thermo camera... but then. £8 vs £300 thermo camera

VERY NICE , BUT WOULD YOU WALK 500 MILE 500 MILES

If you're buying a $7 diamond tester I'm assuming it's to test your fake jewelry

Seriously, a diamond tester and you don't test it against an actual diamond???

Diamonds are a waste of $ for rings But are good at cutting stuff up. This new lab 💎 better be cheaper! Edit: my guess is the tips housing stabilizes the sensors thermal reading. But I would not trust it! Hardness scale exists :)

Brilliant video as always Clive!

Are the big stones (more then 50 0r 100 gram) may tested through this tester

If the sensor is a thermocouple junction then my guess is that the device sends a current through the junction (causing it to heat). When temperature stable, the current is at a minimum (ambient loss). If heat is drawn out of the hot end then current will increase. The op-amp may be used as a precise current sensor allowing the current change to be measured. Change in current would relate in some way to the thermal resistance of the test material. - Eddy

Wonders will never cease. I arrived at the conclusion about measuring temp differential at the same time as you said it, congratulations on pushing knowledge into this slumbering brain "I is lurning"

Are you sure it's a thermocouple arrangement (using the Seebeck effect?) Could it be just a 4-wire sensing arrangement? The current flows through the white wires, but voltage is measured across the enameled wire... I guess that the voltage drop of such short sections of wire wouldn't be high, but the fluctuations in temperature are probably very small...

Computer heatsinks are never anodized, because the process replaces Aluminum atoms with an element that can bond in the same way, im imagining any element with the same number of electrons in the relevant electron shell, which would be 3 if Im not mistaken. Youd have a whole surface layer of poorly conducting material.

HolalepidoporfaborqueinformeCuantoCuestaaparatoparadiamantesGracias

First, the Nooky Pills then a Diamond Tester.... I thought something completely different.........

I own that one you are inspecting so I was interested in how it works myself. But without damaging it since I only used it 2 times and like to in future. If it legitimately works. Thanks!

My friend, who is a jeweler from a family of jewelers, has enough experience to sense the thermal conductivity of a legitimate diamond by touching it to his lips. (You pointed out the ceramic oscillator; I believe my Arduino has a crystal oscillator for the USB timing and a ceramic oscillator for the processor.)

Yeah you did! That and a few helpful comments in the "below" explained most of my questions about this device! So if i got it right this device is pretty much useless to test larger uncut gemstones. Especially those embedded in ore rock?

So would would it be measuring a change in voltage/current because of the temperature difference on both sides of the pin and back to the chip and sending it to the led graph. I thought these might of worked on some frequency the diamond might have. I wonder how actuate they are?💍♨

Also the anodization of the heat sink is a big discussion in computer heatsinks company’s have spent millions on making a coating that isn’t worse than bare aluminum.

It's not that critical which materials they are; any two different materials usually will exhibit the Seebeck effect.

I suspect these things are mostly for show so some disreputable appraiser at a jewelry store can tell you your real diamond is fake but he'll take it off your hands for a couple bucks.

Big Clive: an emergency repair of a battery charger at a hotel involved me using 60sec all purpose glue to secure a plaatic plug thing inside... like inside of PCs ... is thjs likely to set on fire or am i safe

Anodized aluminum has a thick layer of aluminum oxide (alumina) which is electrically and thermally a non-conductor.

The clip would have been even more interesting if there had been a comparison between regular glass and sapphire watch crystal. Many people use these to distinguish between mineral and sapphire watch crystals.

Its because anodizing is non conductive