You think you are an expert? How does this work (UPDATED with solution): - Page 1
Forum section: electronics / general

author: Wartex
author_rank: Frequent Contributor
timestamp: December 20, 2011, 03:22:41 am
content: Edit Jan 2012Solution

author: olsenn
author_rank: Frequent Contributor
timestamp: December 20, 2011, 03:31:46 am
content: I call bullshit!!!!

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 04:28:42 am
content: Quote from: olsenn on December 20, 2011, 03:31:46 amNot really, video editing bullshit is the right word.

author: Wartex
author_rank: Frequent Contributor
timestamp: December 20, 2011, 06:55:46 am
content: For the retards above, there is no video editing.This is doable. 1st and 3rd led are in the same direction, you can see at 2:04 he completes a loop with his fingers and 1st and 3rd leds glow. Switches ARE modified (author claim), I assume they contain diodes, and ON/OFF label has been reversed on some. I also suspect the 9v battery is an AC source (author claims it's not). LEDs might have tiny SMDs between legs.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: December 20, 2011, 07:32:39 am
content: Quote from: Wartex on December 20, 2011, 06:55:46 amTalk about winning friends.....

author: Psi
author_rank: Super Contributor
timestamp: December 20, 2011, 07:44:50 am
content: Yeah, i also though the word "retards" was a bit extreme.But it's probably just a cultural thing, might have different connotations in Canada vs Aus/Nz.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 07:54:16 am
content: Every one is free to show the quality of his character, and the many they can freely choose with who to deal with in the future, and who to discard in the black hole of the toilet.I do not blame Canadians those people are smart, but there is sad exceptions among them too.

author: JuKu
author_rank: Frequent Contributor
timestamp: December 20, 2011, 08:49:08 am
content: Interesting, the same way than other magic tricks. Ok, we can assume an SMD or two between the LED legs, non-standard LED component (does something like built-in voltage monitor circuit LED exist?) and whatever circuit you want inside the switches. He might also have something in his left hand. The switch he's holding on is different than the others (at least the sticker is gone). How? Off-hand, I don't know, but I would say a very clever trick, but not a video edit. There would be no fun in that...

author: JuKu
author_rank: Frequent Contributor
timestamp: December 20, 2011, 02:30:13 pm
content: Also, at 1:40, looks like more stuff inside the LED cover than just the LED. So, what is the real circuit?

author: dcel
author_rank: Regular Contributor
timestamp: December 20, 2011, 02:51:19 pm
content: Neat trick indeed. After reviewing the video, I can not see any devices between the the legs of the LEDs or the switches. The 'misssing' label on the first switch is a matter of the lack of reflected light. At 9 volts, hand contact isn't going to pass enough current to light an LED, so that is out. The switches look as if they are correctly oriented according to their off-on and the terminal positions. Author claims modified switches? I wonder what the mods are? Interestingly, the first switch lights the LED furthest from the switches in the series loop. LEDs won't pass current without illuminating, at least not enough to light other LEDs, they would all glow equally.I'll have to think about this more, puzzles can always be solved...Chris

author: deephaven
author_rank: Frequent Contributor
timestamp: December 20, 2011, 03:22:06 pm
content: If you listen to the sound of the switches being thrown, there is a corresponding echo. Sounds like someone is operating more switches nearby.

author: don.r
author_rank: Frequent Contributor
timestamp: December 20, 2011, 05:00:31 pm
content: Quote from: Psi on December 20, 2011, 07:44:50 amNope. It means the same thing. Look at his posting history...

author: dcel
author_rank: Regular Contributor
timestamp: December 20, 2011, 05:03:30 pm
content: This is what I have found out via translating comments on youtube:Left hand is not hiding anything but a finger nail smacked by a hammer...OP hints that circuit is AC... AC generatior in the batt clip? States that 9v batt is "ordinary"5 ma current but states explaination will ruin puzzle...OP... "But look again and think carefully how many items I really used to build this system?"OP "The third LED went on my mind for years:)I managed to modify the battery or not (as the only element of the film shown).However, the explanation of Usedom, which will provide a sensible systems is hidden in the battery ..."OP "Don't look at my schematic! Consider, how I can? control these LEDs ? Tip: do you know any AC current properties ?"OP "The film is not a photomontage., Or computer animation. LEDs light up as a result of current flow, and not through such laser illumination. I understand that negative opinions is a sign of powerlessness of the intellect. Too bad, because I hoped that this arrangement will inspire food for thought"OP "I used about 200 R. But due to the nature of action, its function is trivial?"OP "We'll talk and how to draw a diagram can show that you manage to pack it into LEDs"OK, so does this mean that he "made the LEDs?" A look at the video may suggest yes, he did, as I have not seen bumpy, poorly cast LEDs even from the Whon Hung Lo brands bulk bagged at the swap meets.So, given the AC supply, the possibility if additional circuitry embedded into the LEDs and probably the switches as well, how?Chris

author: wosser
author_rank: Contributor
timestamp: December 20, 2011, 05:59:33 pm
content: If you freeze the video juuuust before hi flips the first switch you can juuuust see a noodly appendage at the edge of the picture.Ramen.

author: AndreasF
author_rank: Frequent Contributor
timestamp: December 20, 2011, 07:05:10 pm
content: My guess is the switches create or(bandpass)(notch) filter specific frequencies of the AC, and the "LEDs" are somehow tuned to those specific frequencies.How? No idea![Edit: after further thought, filters must be notch filters for it to work, and must be 'active' when the switches are in the OFF position]

author: BravoV
author_rank: Super Contributor
timestamp: December 20, 2011, 07:23:30 pm
content: The AC generated from the "mutant" battery doesn't mean its high frequency, it could be the frequency is so low that probably way under < 1 Hz, and all the switching actions between those 3 switches were very well rehearsed, and the switching sequences must be done with accurate timing maybe ?About the led, its possible they're actually bi-color led but he covered with red dye so which ever led die light up, it still shows red light.Still thinking though ....

author: XynxNet
author_rank: Regular Contributor
timestamp: December 20, 2011, 07:24:25 pm
content: I vote for video editing.Why? Because its the simplest explanation and the lights dont look convincing.Furthermore the author gathers the most attention if he video edits this, denies it and let people speculate...and attention is obviously his goal. If you just want to show a neat trick you usually explain it afterwards.

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2011, 07:36:23 pm
content: Quote from: XynxNet on December 20, 2011, 07:24:25 pmIllusionists never give away the secret of how a trick works. It spoils the illusion.

author: don.r
author_rank: Frequent Contributor
timestamp: December 20, 2011, 07:52:47 pm
content: I don't think the video was edited. I have seen plenty of evidence in it that its genuine, particularly where the LED lights his finger when drawing the ? mark.

author: Wartex
author_rank: Frequent Contributor
timestamp: December 20, 2011, 10:58:05 pm
content: Quote from: Jon Chandler on December 20, 2011, 07:32:39 amI couldn't care less about strangers on the internet who contribute nothing of value besides screaming "bullshit" to the discussion at hand. Kiriakos already proved to be a socially awkward buffoon with personality problems, I don't want him to be my friend. I don't know these people, they don't care about me, I'm not going to go out of my way to accommodate them. For all you cigar-smoking, top hat and monocle wearing armchair professors: "retard" in internet lingo means "a fool".Even if this circuit is faked via non-electric means, it's still a good brain exercise. Lasers were nothing but sci-fi tales in the past, now we have them in every facet of human life. I'm sure there is a solution to this, be it trivial or complex, we can find it and let's concentrate on it instead of teaching me social interactions, shall we?

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 20, 2011, 11:37:16 pm
content: If you wish to care about your opinion post your full name and a picture of your self with cloths on this time.Up to today, you did not manage to fool me buying your worthless used instruments that you fish on ebay, and try to make money from them.Your pitiful videos its not my business either, but only one true "fool" would take as footage the toilet seat of his home, or he would take a video of him self by be on the bed naked (only underwear) taking footage of the device in his hands and his naked legs.Your latest incident, about trying to make fool Dave Jones about a single word like "calibration", it was the latest proof that I needed so to be 100% sure,that you are asickperson in a way.Ask for help from the experts, you do need it.

author: amspire
author_rank: Super Contributor
timestamp: December 20, 2011, 11:58:45 pm
content: I don't know how the trick was done, but if I wanted to duplicate the trick, I would just do it the simplest way.I would make sure the battery connector was open circuit, and have one or two very fine copper wire pre-soldered to each of the LEDS. A 1 thousands of an inch diameter copper wire would work fine, and it would be completely invisible to the camera.I would use foot switches to change the LED's.There are far more complex ways of doing it - those switches can easily be disassembled so you could add components inside the switch - but why bother? It may be possible to have RF antenna's directly under each LED, and if you turn the RF up enough the LED lights (the left LED was aligned to a reference dot on the paper), but the invisible wires is a better solution because it is simpler.Richard

author: joedevola
author_rank: Contributor
timestamp: December 21, 2011, 12:22:00 am
content: Aspergers is 'the engineers disease', so you will probably find that a higher proportion of people here are aspiesThere are various levels of 'functionality' and many have worked out that if you want to participate in social endeavours, even online ones, a certain level of polite behaviour is required, even if you don't want the other participants to be 'your friends'

author: Wartex
author_rank: Frequent Contributor
timestamp: December 21, 2011, 01:09:30 am
content: Quote from: Kiriakos-GR on December 20, 2011, 11:37:16 pmI think you are confusing this forum with a gay dating website.QuoteIs that somehow illegal or immoral? Are you aware that millions of people make their living that way? Oh, my thermal imager that you couldn't afford, and my 8.5 GHz spectrum analyzer and countless Fluke DMMs are hardly worthless. I don't scam manufacturers into sending me free gear like you do. You are just a jealous loser, enjoy your Agilent with a huge markup and VAT slapped on it.QuoteAre you going on about naked men again? What was that history says aboutproliferation of pederasty in ancient Greece? Keeping the tradition I see? Sorry I offended you by my shorts, next time I will wear a burqa.QuoteI wasn't trying to make fool of Dave, I was pointing out that there is more to calibration than just verification and later he said he "calibrated" his Gossen, clearly meaning he *adjusted* it and not calibrated it.Quote

author: don.r
author_rank: Frequent Contributor
timestamp: December 21, 2011, 02:02:18 am
content: Quote from: ErikTheNorwegian on December 21, 2011, 01:51:48 amSometimes it is hardest to see that which is right in front of you... or within you.No snow here yet.

author: Unknown
author_rank: Unknown
timestamp: December 21, 2011, 02:23:02 am
content: The one constant being that whatever the shitfight on this forum, Kiriakos is always contributing at least his 50%.The Greek, Internet, equivalent of Pattinson's Curse.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: December 21, 2011, 03:19:42 am
content: Quote from: Uncle Vernon on December 21, 2011, 02:23:02 amThe forum Ghost came back from the Grave for another rematch and killing his boring to death free time.With all this madness you have greatly damage this forum.But why to care about it ?Oh I just remembered it , this is not a forum is the tea cup of Dave..

author: vk6zgo
author_rank: Super Contributor
timestamp: December 21, 2011, 04:42:03 am
content: Quote from: Wartex on December 20, 2011, 06:55:46 amFrom the evidence you presented,us "retards" could well be forgiven for considering it a video fake.Only by chasing it up on Youtube was I able to findanyinformation from the original poster on that "forum".Even then,I didn't find any claim of a modified switch,or denial of an AC source,but unfortunately,I could only read the English content of the comments,most of which were also shouting "fake"!Most of us "retards" are not sufficiently gullible as to take the original video author's assurances as Gospel,&looked for a more rational answer to what is,if it was true to the schematic,& the visible wiring,impossible.VK6ZGO

author: Wartex
author_rank: Frequent Contributor
timestamp: December 21, 2011, 04:49:42 am
content: Quote from: ErikTheNorwegian on December 21, 2011, 01:51:48 amOne of the first things a psychiatrist will tell you about DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) books is that laymen should NEVER EVER read them because there is 100% chance of multiple, completely wrong diagnoses. If you read DSM-IV you will find that you have symptoms of all kinds of mental disorders. Asperger's syndrome is revealed in manifestation of certain traits, emerging behaviors and can only be properly confirmed by a trained psychiatrist. Being socially awkward is absolutely no way related to having AS. People online who call someone highly functioning autistic or having ADHD or Aspergers without any proper training are just stupid assholes who talk out of their ass, ignore them. Statistically, there is virtually no people on this forum that have any serious mental deviations. I have a short fuse and very direct way of saying things, and I think Kiriakos is just lonely (at least internally) and has a lot of misplaced enthusiasm. I don't truly believe he is a moron or inherently evil bastard, I think he is just "attention whoring".We are ultimately here to draw information and share experience for the common good. We strive as a group, but on individual level no one gives a shit about anybody else. If one of you died tomorrow in a car fire, Dave or anybody else wouldn't give 2 shits about you, just face it. It's not because we are emotionless drones, it's because there is no personal emotional attachment, we are just "avatars" online. And don't idolize anyone, please.There is a petty argument that pops up here and there and we need to either make it comedic or stop it right then, otherwise S/N ratio of the forum gets really low. There are some moderators here who shall remain unnamed who have 1000+ posts and there is literally and dozen of post that are of real value, the rest is just generic, irrelevant fluff.This thread is not about aspergers, Christmas or me or Kiriakos. This thread is about finding a solution to the puzzle. So far I have seen ONE weak and not really applicable solution. Please get back on topic.

author: Wartex
author_rank: Frequent Contributor
timestamp: December 21, 2011, 05:15:00 am
content: Quote from: vk6zgo on December 21, 2011, 04:42:03 amLucky for me I speak more than 1 language and I can read Polish. He stated that the circuit has missing components but is serial like drawn, and some components have been added but not visible. I am not asking to guess how 3 incandescent bulbs in series can be controlled with series switches, am I?The point of this exercise is to find our own plausible implementation of this. Here's one:Hackaday comments for more ideas:http://hackaday.com/2011/12/19/ask-hackaday-troll-physics-edition/#comments

author: joedevola
author_rank: Contributor
timestamp: December 21, 2011, 05:20:26 am
content: Hey Wartex, you have just added to the S/N ratioAnyway, I was not 'diagnosing' anybody, simply making a comment to someone who revealed that they have been diagnosed. For what it is worth, the statement about engineers having a higher incidence of Aspergers is a statement of fact, not a diagnosis. You are correct about lay-opinion about reading the DSM, however my observations are based on both living with my son whoisdiagnosed with AS and having been diagnosed myself. Having said that, AS does appear to be the 'flavour of the month' diagnosis, like ADHD wasEven if you don't want to be my friend, I wish you a merry ChristmasPS, I am interested in discovering the 'trick' of that video too

author: BravoV
author_rank: Super Contributor
timestamp: December 21, 2011, 07:13:18 am
content: Quote from: ErikTheNorwegian on December 21, 2011, 12:14:44 amLike this here ? ->https://www.eevblog.com/forum/index.php?topic=5458.msg71160#msg71160Quote from: Wartex on December 21, 2011, 01:09:30 amForget about expensive gears, apparently you haven't seen the "better" one, here a fine example of a really pathetic attempt to scam few of these lowly cheap onehunglow nimh batteries like this here ->https://www.eevblog.com/forum/index.php?topic=5327.msg69783#msg69783Just worry these kind of activities will affect/hurt Dave's reputation among manufacturers, cause there is a possibility that this kind of "beggars" are riding this website's popularity, and they're sorta claiming that its a collaboration work with Dave in order to keep these scams going, who knows ? Especially those Chinese manufacturers that most of the times we know that they're quite poor in English and its quite logical that within thousands of attempts which cost them zilch, they might scored a few successes.

author: LEECH666
author_rank: Frequent Contributor
timestamp: December 21, 2011, 07:35:29 am
content: Quote from: vk6zgo on December 21, 2011, 04:42:03 amThis is exactly what I thought. The video posted on Youtube fails to assign you the task of thinking a little deeper. It fails to tell you "hey these components might not be what they look like", and the shematic makes it easy to assume the whole thing is fake/edited with after effects.

author: JuKu
author_rank: Frequent Contributor
timestamp: December 21, 2011, 08:43:13 am
content: Hi Wartex,Congratulations! Your circuit is much simpler than the one I explained this to myself (three oscillators, three band-pass filters). The batter is likely just a battery, but there is an oscillator somewhere, either inside the first switch (he had to remove the sticker to pry it open?) or inside the battery connector. Just guessing...

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 21, 2011, 08:52:15 am
content: Why bother, it cant and will not work, ever and never

author: SgtRock
author_rank: Unknown
timestamp: December 21, 2011, 09:49:31 am
content: Greetings EEVBees:--Ah, once again we hear from UV, alias Frack. He has had Kiriakos on his ignore list for lo these many months, yet he still rings in with nonsequitur, every time he sees Mr. K mentioned, even when he does not know what has been said. "See, I cannot see what you wrote, but you have to see what I wrote, ha ha ha." Frequently he begs, and pleads, and whimpers, for people to add Mr. K to their ignore lists. Not satisfied to insult Mr. K, frequently, he has to insult the entire Greek nation. What class! How infantile! Too bad a dingo did not get this baby.--"There once was a nuncle called Vernon,Who had a real problem learnin'The folks he'd implorehis foes to ignore,so hot was his jealousy burnin"Gator Dundee 1948 ---Ah, then of course we have Wartex alias Fudd, who gets weally weally angwee when anyone disagwees with him. Sometimes he posts in truly huge fonts, in order for us to catch on to how "weally weally angwee" he is. His latest kick is to hold the entire Greek nation and Mr. K in particular responsible for pederastic practices in the Greco-Roman milieu more than 2000 years ago. This subject seems to hold a strange fascination for this erstwhile denizen from the land of Moosehead and Cedar Shakes. You know the place where the Canadian Human Rights Commission tried to censor Mark Steyn in perpetuity for quoting hatemongers and preachers of violence in an article in Maclean's Magazine. Do you think we should blame Fudd and everybody in MacKensie Paper Towel Land for the transgressions of the Ottawa fascists. I do not."There once was a spammer named Wartex,Whose mind was pulled into the vortex.His rage was so manic,He'd post fonts gigantic,To ease the great hate in his cortex.Gator Dundee 1948 -Best RegardsClear Ether

author: PeterG
author_rank: Frequent Contributor
timestamp: December 21, 2011, 09:59:13 am
content: Quote from: SgtRock on December 21, 2011, 09:49:31 amWell said.Regards

author: vk6zgo
author_rank: Super Contributor
timestamp: December 21, 2011, 10:17:07 am
content: Gee,that was fun!Getting back to the original topic,however,I still have a problem with your circuit,Wartex.I can see how Sw1 & Sw3 would turn on their associated LEDs,but I have a bit of a problem with Sw2.How about a description?VK6ZGO

author: EEVblog
author_rank: Unknown
timestamp: December 21, 2011, 10:33:30 am
content: Ok guys, knock it off.I'm seriously contemplating going through and deleting every personal attack post in this thread regardless of whether it has content or not, and the thought of having to do that just pisses me off and ruins my day.Cut out the personal attacks, please. I don't want to have to heavy hand moderate this forum.But given the choice between enforcing moderation or just letting the personal attacks continue, I'm going to have to reluctantly chose the former.Dave.

author: samgab
author_rank: Frequent Contributor
timestamp: December 21, 2011, 10:39:57 am
content: I'm going to have to go with Occam's razor on this one.There is probably some really complex and elaborate electronic method to do this trick, but it would take about 5 mins with Final Cut Pro to "light up" those LEDs.If it's not editing, then it may just be lens flare; but there is a bit where the light is in front of his finger:Dave, any ideas on how this might have been accomplished?

author: EEVblog
author_rank: Unknown
timestamp: December 21, 2011, 10:49:06 am
content: Quote from: samgab on December 21, 2011, 10:39:57 amI just watched it and haven't given it much thought. But obviously:- The battery can be hacked. Likely a bunch of cells removed and replaced with some circuitry. Even the battery snap could have something in it.- The LED's could be drilled out and replaced with a tiny SMD led and some circuitry, and then re-potted with leads. Very fiddly, but possible I think.- The switches are big, probably for a reason. Once again, circuitry internal very likely.With any or all of those things, pick your method of control...Dave.

author: ejeffrey
author_rank: Super Contributor
timestamp: December 21, 2011, 11:27:15 am
content: How about this: You drill the LEDs and put a dallas 1-wire switch like the DS2405 or DS2413, a zener shunt regulator, and an LED. You wire up as many devices in series as you want with a current limiting resistor. The battery can be just a battery. Each switch contains a small microcontroller powered by its own coin cell and a normally closed MOSFET switch shorting the switch terminals. With a bit more care you could probably have the circuits in the switch powered by the battery, but a small coin cell easily fits and makes things simpler. Now, when you flip a switch, the microcontroller opens and closes the switch to transmit the 1-wire address of the corresponding LED, causing it to toggle. You are limited in the number of LEDs only by the available battery voltage. A 9 V battery should be able to do a chain of 3, but you could easily fit a higher voltage battery in a 9V battery can. Sounds like a right pain in the ass, but it should be doable.

author: EEVblog
author_rank: Unknown
timestamp: December 22, 2011, 02:47:11 am
content: Thread cleaned up with all last comments deleted as a matter of course, I hope everyone understands, and that it never has to happen again.Kiriakos has been banned, I've had enough pot stirring.Back to your regular scheduled thread...Dave.

author: ron
author_rank: Regular Contributor
timestamp: December 22, 2011, 05:58:56 am
content: Whew! Back to topic.Could this be accomplished if the "battery" is a pink noise source and the switches and LEDs have selective RCL bandpass circuits. Not an EE, I don't know if the actual miniature components exist. But this is similar to an old problem that we solved with Fourier analysis. I'm just a retired physicist and I was taught that when you need to design a chicken coup -- assume a chicken is a sphere. Please take it easy on me if I'm way off base.This sort of reminds me of the dubious 555 easter egg (EEVblog#160). Only not as funny.

author: dcel
author_rank: Regular Contributor
timestamp: December 22, 2011, 03:05:40 pm
content: I have been to the battery manufactures website and compaired the battery in the video to the battery on the site and they are NOT identical. So, it is entirely probable that the battery in the video has indeed been modified. Now, the question is HOW was it modified? It was also suggested by the videos creator that every item used the make the circuit needs to be considered in the function of the circuit.Chris

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 22, 2011, 04:19:33 pm
content: He added at least one AC source. Possibly by taking the battery apart and a small battery + circuit in the case. Or maybe just inside the battery clip. Not much space, but doable. Squeeze better to add two AC sources and you can drive four leds, like my circuit.

author: don.r
author_rank: Frequent Contributor
timestamp: December 22, 2011, 04:58:24 pm
content: Unfortunately, this kind of exercise is not so much of a puzzle as a "what circuits can I squeeze into other components" problem.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 22, 2011, 06:32:29 pm
content: Quote from: samgab on December 21, 2011, 10:39:57 amThis is a good catch and looks suspicious

author: Short Circuit
author_rank: Frequent Contributor
timestamp: December 22, 2011, 06:40:52 pm
content: Just from youtube:Quote

author: Lightages
author_rank: Unknown
timestamp: December 22, 2011, 09:48:50 pm
content: Instead of making us search for the answer, why not provide it in your post here too!

author: Wartex
author_rank: Frequent Contributor
timestamp: January 27, 2012, 10:17:13 pm
content: Official solution:You crafty SOB! I knew the coil was around the LED, assuming it was really thin wire, but he went even further and filed a channel around the LED to hide it. The generator and all components fit in the battery connector - battery was unmodified just like he said.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 28, 2012, 04:58:45 am
content: My head hurts!VK6ZGO

author: johnwa
author_rank: Frequent Contributor
timestamp: January 30, 2012, 09:04:37 am
content: I saw this a while ago, and managed to come up with an equivalent circuit, but I only got as far as building it up on a breadboard. (I had seen the solution for two switches and lights a while ago.) I hadn't really looked into the physical constraints on component size - I presumed that there was just a chip inductor across the third LED - but the necessary values may not actually be available that small. Winding the coil round the LED is a neat trick!I thought this puzzle was quite a nice exercise - it is not so much about the solution itself, as seeing if you can figure it out for yourself. Perhaps we should have some electronic related puzzles here on the forum for people to think about. Something along the lines of what they used to publish in 'Electronics Australia'?John