Julian's Postbag: #99 - SuperCapacitors and Computer Chips

[@The.Doctor.Venkman]

I love your voice, Julian. The whole family has become used to hearing you in the background everyday! I just love the mellow tones of your commentary and the way your mind is so inquiring and wants to figure out what is going on. I wish some more of our Electronics & Electrical Engineering lectures at college back in the day (1982) had been of the same disposition. Some were, and I remember them fondly. You would have made an excellent lecturer!

[@JulianIlett]

Thanks Andy - much appreciated :)

[@CharlesDParker]

Well said.

[@mynameisnobody1fjb372]

crocelian, you don't realize that not all the Julian followers are know it all like yourself, and some are beginners, or just people that enjoys his style, and people that used to be into electronics a long time ago, and Julian refreshes memories with the archeology electronics. You are a gamer, why bother?

[@Teukkaniikka]

I would really like to see some more projects from you! Postbag is still one of my favorites! Keep the good work going!

[@Anvilshock]

In this video, Julian drives viewers mad who have begun building their own breadboard computers according to his specs, and are now sitting on a pile of freshly ordered LS ICs that won't get used in the actual build anyway, and have to reorder everything in HC and HCT. Thank you, Julian.

[@JulianIlett]

It's simple - when the design is finished, I will draw up schematics. Until then, the design is likely to change :)

[@tonydoyle6641]

Just to say i started on computer last year age 70 as a past time and you and others are fantastic .For your next vid congrats on your 100 best regardsand go back a few .Only started these kits last nov and im hooked love your post bag TONY FROM CORK IRELAND

[@domramsey]

Much as I enjoy seeing you open stuff, I'd much rather watch you make the actual projects!

[@stevekelsey411]

I enjoy the way you explain all the items and why you bought them. thanks for all of your videos

[@txtigr]

Hi Julian, really enjoy your videos. I often see super cap stuff where it might be helpful for a simple way to figure out the absolute maximum equivalent mAH power instead of just volts and farads. Obviously this will be a bigger number than reality due to all the losses in reality. But to figure the "top end" of your system, here is the calculation: Power in a cap is J = 1/2 * V^2 * C. So for your 2.5 v 700F that is gives J = 2187.5 joules. A Joule is a watt-second, so divide by 3600 sec/hr to get P = 0.6076 watt-hours. Since a watt is volts * amps you can divide by volts to get AH = 0.2431 Then convert to mA by multiplying by 1000 and your maximum for the cap is about 240 mAH. From there you probably should multiply by 0.67 to get in the ballpark for a real discharge curve and you will get about 160 mAH. Reality will be less, but that should give a general idea of what you are dealing with. I hope this is useful; keep up the good videos and fun experiments.

[@CharlesDParker]

I do like your Postbag videos. Time to celebrate the Julian's Postbag: #100 ! I'll be watching. Thanks.

[@alexandermay861]

Postbag #100 is around the corner!

[@mynameisnobody1fjb372]

Hello Julian, I wish you could do an in-depth series on assembly language, your style delves well into the minor intricacies, and explore all details that even a collage course fails to address in my opinion, just a wish. Please keep up the great work, you are teaching a lot of the future engineers and hobbyist a great deal. Cheers, and thank you. F.

[@JulianIlett]

I'm doing just that with my PIC programming tutorial series. But it's getting very low viewing figures - it's difficult for me to remain enthusiastic about it.

[@emerituse3390]

As it's probably already been mentioned, yes, those silicone plugs are pressure relief vents, so in the case of catastrophic failure, you don't end up with a huge explosion and aluminum shrapnel embedded in everything.

[@AdrianTechWizard]

Hey Julian, When you're soldering the 0.1" header on the SMD breakouts absolutely use a breadboard for stability but do *not* do the SMD work in the breadboard (if you use a hot air station), you only know you've ruined your breadboard after the fact. On the other hand you could use the crappy breadboards...

[@genemayne1577]

Julian.do you still use your 12v Grid-Tie Inverter . I have 2 x 100 watt panels which are doing nothing now and i would like to get a 12v Grid-Tie Inverter but i have no idear what i should be looking for can you help me out please gene .....

[@UpcycleElectronics]

Spoiler Alert: In postbag 100 Julian reveals he makes a living as the eBay seller Alice1101983

[@dantronics1682]

Hi Julian Robert Murrey smith said he was making some supercap and he mentioned that you were interested in testing some, If you did can you let me know which video is covering this please. thanks

[@ParedCheese]

Yes, the silicone plugs are intended to blow out if pressure increases in the capacitor. 😉

[@RSOFT92]

There is a Video from Photonicinduction, where he kills some big Capacitors with a Welder, which shows the Plugs in action.

[@PhilXavierSierraJones]

I'm having problems with Rohm Unisolated DC-DC Converter chips used in Hortron IR door sensors -- I'm trying to tap off 3V (+/- 0.25V) from 5V line and connect it to a doorbell circuit that operates at 3V, but despite the voltage divider providing near-perfect 3V even with the bell connected, it refuses to work. (The line isn't being loaded down by the circuit, the voltage is stable, and bell section works perfectly when fed with 3V from external power, rated at 3V 0.125A) I can't even find the datasheet for this particular one so I used my only multimeter (notice it's not DMM) to find the 5V line which is supposedly used to run the internal CPU. I can't order any more parts so I had to come up with something that could convert 5V to 3V, but apparently mine isn't working. Resistor divider value: Vcc - 10K - OUT - 10K - 10K - GND What could be the problem, and how do I find the faults with minimum amount of tools?

[@RWBHere]

Two 10k Ohm resistors in series across 5V means that total current through the resistors is 1.25 mA. That's the problem. Why not use 3 Silicon diodes (chosen to be able to handle the current required by the load) in series with the load, and use the 5V supply? Each diode will drop between 0.6 and 0.7 Volts, so the load would 'see' between 2.9 and 3.2 Volts. Add a 1k Ohm resistor across the '3Volt' connections to clamp the voltage to 3V when the load is disconnected, for extra safety. Dead simple and robust. You could use a zener or a voltage regulator, instead, but you only have 2V of overhead, so the diodes are probably your best option.

[@RWBHere]

My bad; make that 0.25mA through the resistors, for 20kOhms across 5Volts. Must stop doing mental arithmetic at night, after taking my ugly pills!

[@spikeydapikey1483]

Always enjoy a postbag video :O)

[@JanRasmussen]

Maybe you could spare one of the 10 bit bar graphs to use all 10 bits for one of the 8 bit computer ALUs - so that you can have a Carry, Owerflow, or similar flag on the 9th and 10th bar, +Julian Ilett ?

[@alankingvideo]

Did you say you are going to use a sil resistor array? Why not use a single power resistor with a common cathode for all your leds?

[@ufohunter3688]

You might be interested in building an R-2R DAC (x2) for your VOCODER project. As you know with a serial to parallel output latch (74HC595) and R-2R ladder resistor network, you can built a flash DAC? Very high speed and accurate and tends itself perfect, with a retro project like yours. You bought a lot of 1% resistors lately. Hand pick some (10k, 10Kx2 for the R-2R) , and you'll have a precision R-2R resistor ladder network on the cheap. Just a suggestion. Entertaining video as usual :)

[@ThatGuy-nv2wo]

Why do the caps have dents? Strange design choice. I like your solution for SIL LEDs, but why not go with an 8-bit segment?

[@kewakl8891]

The dents are called rills. According to the CornellDubilier documentation: With rilled construction the element is secured by rills, spoon shaped dimples in the side of the can. Rilled construction offers the industry’s highest vibration and shock withstanding and excellent heat transfer. Besides increasing ripple current handling, the rilled construction extends the great value of the Type 3186 into military and transportation applications that require rugged mechanical capability. Other options might include filling the empty space with some other medium.

[@SirArghPirate]

what is considered a safe charge current for such capacitors?

[@rocketman221projects]

The datasheet doesn't say what the maximum current is. The internal resistance is listed as 4 milliohms. I would say about 30 to 35 amps would be the maximum continuous current. That would dissipate 3.6 to 4.9 watts.

[@raymondheath7668]

I hadn't thought of swapping out bus chips for the 500 series where the bus is all on one side, simpple and elequent way of making the wiring neater

[@TheDutyPaid]

16:10 "500mm" so half a metre across?

[@pkacc1]

1 mil = 0.001 inch. Breadboard pitch is 0.1 inch.

[@jackdawes8264]

So why is a thou now a mil? ... inflation I imagine.

[@tin2001]

Jack Dawes Because America, probably.

[@davegeorge7094]

5 of those Nippon in parallel looked indented when new then filled out hard and round after a week of charging and leakage when down to about 2mA! I found precharging in parallel is best in voltage steps to reduce power waste. See my other JI post for further details. I use a CV curent limmited supply to condition super caps. Always put new one in parallel when conditioning. I was frustrated by power wasted by the farad tolerance activating protection circuits in series cap batteries.

[@TheDutyPaid]

Could you open a super capacitor some time, just to make sure it is not a lower value cap hiding in the bigger can.

[@zaprodk]

A test would show that; no need to destroy anything.

[@TheDutyPaid]

www.eevblog.com/forum/projects/warning-fake-large-electrolytic-on-ebay-!!/

[@sparkyprojects]

Did you notice the LOL on those 138's ? :D btw, amazon has the dip version of those

[@MikesDIYTeslaPowerwall]

Another good Postbag

[@davegeorge7094]

I had heat problems at 20Mhz clock with 4, linked 74161 counters. I solved problem with heat sinking. The carry pulse is only >50nS so it went to a F/F clock input to reload parallel counter inputs. My 1st big digital design of the 80's

[@taaviparn9175]

Did you say 600mm about a 60mm ic?

[@Martin-uf4ut]

can I have a list of good search terms for eBay of cheap electronics goodies to buy. I'm struggling for inspiration

[@lillydoye7418]

martin Peters diy electronic kit gets a good selection of simple, cheap kits.

[@tonezoneuk]

Is there a reason why super capacitors are always low voltage. Can they not produce 10v for example.

[@RWBHere]

he dielectric later has to be very thin in order to achieve high capacitance for a given dielectric material, plate area and package size. This thinness means that it cannot handle much voltage before it arcs and damages the dielectric layer. If you want twice the voltage capability, you need about twice the dielectric thickness and four times the total capacitor plate area, so higher voltage capacitors are inherently much bigger in volume than supercapacitors. Think of these as miniaturised capacitors, if you like.

[@SolarizeYourLife]

Why do they make them at 2.5-2.8 voltage? Why not higher?

[@JulianIlett]

Limited by the electrolyte - it will start to electrolize at higher voltages.

[@roidroid]

i have some SMD to SOP converters like that. The PCB width is 600mils (15.24mm) edge to edge, or 500mils (12.7mm) pin to pin.

[@JulianIlett]

Perfect, thanks :)

[@bernt6500]

what is the difference between supercapasitors and normal battaries

[@QLTD]

Super capacitors are more reliable, batteries die quicker

[@shoopnooop2952]

You can charge and discharge them a lot faster and go all the way down to 0 volts. They also work better in higher heat products compared to lithium batteries. They have a lower energy density but you can charge them more times than normal batteries.

[@bernt6500]

shoopnooop thanks a lot

[@lachieblack9234]

batteries store energy in the form of a (sometimes reversible) chemical reaction, supercapacitors are very large, high capacity capacitors. they store energy in the form of an electric field between charged plates.

[@simonhopkins3867]

once back in work I'll be contributing to patron on several chanels.

[@Mr7yhnmki8]

On the LED bars, drop one LED from each end. It will look better.

[@JulianIlett]

+Mr7yhnmki8 I didn't think of that. I agree, it would look better.

[@tomaszzaborek4413]

Thank Julian for subtitle!

[@km5405]

julien, how about using headers in some prototyping board and soldering the IC directly on the solder keeping the headers in?

[@justbearwithit1642]

Can you give me a link to that constant load, Julian? I'd like to use it with a solar panel to charge my SLA 22Ah battery. (presuming it doesn't get blown sky high like the last one I used did.. a 10A LED driver blew up when I tried using it several times, I think rectifier failed catastrophically or sometin)

[@-yeme-]

its not a battery charger or charge controller, I dont see how you could use it to charge a battery. likewise an LED driver, which will deliver a constant current but doesnt have the voltage cut off you need in a battery charger

[@AsafShahar]

The easiest way IMHO is measure the total energy of the cap. you can do that with an arduino. Then calculating the capacitance is pretty strait forward (e.g E=1/2*C*V^2)

[@SantaClaw]

My first thought was that the rubber thingy was some kind of reset button for a built in fuse/protection

[@RWBHere]

It's a pressure release valve. I was hoping that Julian wouldn't try pulling it out!

[@QLTD]

4:03 that speaker looks second hand not new!

[@kose2ik]

1:03 soft-disloading (button+resistor)?

[@jparky1972]

Hi Julian. I was wondering how much of your eBay purchases come either incorrect, broken, faulty, lost or otherwise wrong? Personally, my experience has been around 1 in 10 items from asian sellers are in some way incorrect.

[@SidneyCritic]

Out of 300 orders I've had 4 lost and 3 faulty or wrong items. I made a Excel sheet to warn me of lost items before the 50 day limit, and to track who delivers the fastest.

[@jparky1972]

SidneyCritic ComedyHound You've been a lot luckier than I have then. I still mostly buy my electronics pieces from Asian sellers anyway as it's typically the same items that come from UK sellers. Just less than half the price. I'm happy to wait too. I've only been stung by two or three sellers but I've been stung by more UK sellers than Asian sellers.

[@AJB2K3]

If they are to be believed, they are supposedly made in Japan (Nippon) however the printing looks fake.

[@zaprodk]

I agree. They are clones.

[@victorfontaine8706]

I don't hunderstain what's the difference between a super cap and a batterie

[@lynnnash4576]

I am going to start with the assumption that you know a battery can take a long time to charge up to hours. a capacitor for simplicity sake charges almost instantaneously if you let it, more in a moment. When I was in Uni I had a professor make the statement that we would "never" see a 1 Farad capacitor small enough and light enough to hold in your hand, well a super capacitor is just that using thin layers folded back and forth. ok so what allows it to charge so quickly without the physics. A capacitor will reach its max charge in 5-time constants (T) in seconds. In the first time constant it charges to 66 and two-thirds of max potential math T = R x C where R is series resistance and C is Farads. Second-time constant we charge to 66 and two-thirds of the remainder max potential; third time constant 66 an two-thirds of what is still remainding; rinse and repeat for T 4 and T5. Discharge is the reverse, it will release 66 and two-thirds of its stored energy unless the current flow is limited. This is how they make those little tiny boxes that can jump start an automobile. There is more to it than what I have described but I'm keeping it simple

[@cengland0]

Those 74HCT138 have active low outputs so you're going to be surprised when all the outputs are high except one at a time. LLL input will give you HHHHHHHL output.

[@JulianIlett]

Perfect - the enable inputs on the 74HC574 and 74HC541 are active low too :)

[@cengland0]

Okay, I thought you were going to output them to your LEDs and it would be awkward having 7 on and 1 off.

[@ElmerFuddGun]

Postbag 99 - oh boy now I am wondering what is in store for the *big 100.* I bet Julian already has it planned. Maybe even already recorded!

[@JulianIlett]

Planned but not recorded :)

[@maicod]

maybe a 3D printed Julian figurine

[@retiredwizard]

They are a bit more expensive but you can get the through hole SN74HCT138 chips from Mouser. www.mouser.com/Semiconductors/Logic-ICs/Encoders-Decoders-Multiplexers-Demultiplexers/_/N-4s67oZscv7?P=1z0z63x&Keyword=74hct138&FS=True

[@donaldfilbert4832]

Julian !! What do you do with all of this stuff ? I have been following you for some time - and you have accumulated an enormous amount of electronic components and gadgets - smile. By now - I would think you'd need a warehouse - or perhaps move to a larger house - laugh !!

[@JulianIlett]

Certainly I could use a curator to keep track of it all. These days I can never find anything :(

[@donaldfilbert4832]

Now THAT I can relate too !! laugh !!

[@drewhodge3820]

I would like to see a vehicle jump starter built from super capacitors

[@CyberlightFG]

andrew hodgkinson I don't think, these capacitors can handle that high current

[@samuelseidel6148]

My electric load has the exact same character messed up.

[@maicod]

the white thingy looks like a test button but it probably isn't :)

[@TheViewFromUpHere]

Lots of SO16 to DIP adapters on eBay.

[@TheShivbabber]

Do a history video, I've been watching you for a year now!! But you never have mentioned what you did before you did KZbin full time!!

[@JulianIlett]

I have talked about my background in my live streams

[@TheShivbabber]

Oh okay I'll go have a gander through your streams! Thanks for a personal response Julian! My celebrity crush has been fulfilled!

[@kewakl8891]

Rubber cylinder is called a 'vent plug.'

[@martinda7446]

TLO84 found in almost every Hi-fi product made since 1976. Ubiquitous innit.

[@shoopnooop2952]

The bar graphs seem like they would be neat to be used in watch project.

[@MonaichFother]

I hoped he was going to use them in the speaker project. :]

[@JulianIlett]

As a capacitor voltage indicator - nice idea :)

[@MonaichFother]

Well, I was originally thinking of blingy volume meters on each speaker :D

[@Anvilshock]

That would be up to 200 milliamps of additional load on the capacitor ... just to show how much is still left in the capacitor.

[@shoopnooop2952]

All you have to do is put a button on it so you can press the button to check.

[@gandsnut]

As Alice1101983 and I are 'struggling' with their utter failure to provide support on one item they sell, this mailbag prompts me to ask our host about his assessment of online sellers, generally. Seems there's too much misrepresentation of their products/specs, and/or they claim inability (or just refuse) to provide support. Buyers of, say, 6 years recent appear OK with the attitude, "oh, well, it's [foreign rubbish] - par for the course". If buyers go laissez faire about the quality of their own transactions, sellers aren't about to work hard to be responsible... much less to show integrity or conscience about what they do. This new paradigm really rubs me the wrong way. Thanks!

[@joeambly6807]

Its because you have different cultural expectations. Bunny has a great assessment of the differences between asian and western buyers. Expect misrepresentation, and dont be suprised that cheaper itemns are not the saame quality. lol. Easy Peasy.

[@joeambly6807]

The companies that manufacture airplane components are not penny pinching hobbiests and have quality control and government regulations. APples to oranges. Why must customers concede? Its not conceding, you can choose to support these sellers or not. YOU as a buyer must understand what you are buying. Dont buy from china if you dont want to deal with possibly questionable compionents. Simple as that. Its not julians responsibility to wax and wane poetecially on your gripes with westerners.

[@joeambly6807]

Apparently you are only rubbed the wrong way because of a bad transaction. Get off your high horse and start speaking normal english you pleb

[@joeambly6807]

wtf are you talking about

[@RinksRides]

if you were any kind of diabolical, you'd make a railgun! (gauss gun)

[@squnxfisher9831]

noo don't keep your boxes there taking over! nah just a joke ;) but that is what happened to me I have so many empty boxes... I don't know where to put them

[@StresSdidri]

White rubber is for adding electrolyte with a syringe in the unit

[@evilution_ltd]

Tudorache Adrian no.

[@theredredstonesolar4996]

try aliexpress.com it is cheap

[@macdonalds1972]

4:10 That is one crusty looking speaker.

[@maicod]

its probably 2nd hand

[@browaruspierogus2182]

Those caps are now 3X more. Ridiculous

[@DoonRiderMaharsh]

Sir why dont you make a smd to dip socket at home and do a pcb etching tutorial plssssss make a videos on this plsss

[@RWBHere]

That would not be easy to do at home for most people. Those pads are tiny.

[@Brant_Channel]

lots of toys!

[@TheTeamScorpia]

seems like youve overcome your fear :D

[@jort93z]

why do all those shenzhen/china packages look like bombs? xD. sometimes they even wrap lots of duct tape around it. can't they use actual boxes lmao. i kinda find that amusing.