Electrical Engineering V2 - Developers

Hey guys, this might be a bit of a rookie question because I'm still rather new to electronics, but here goes: I'm trying to figure out exactly how those "Prank Shock Gum" toys work. I actually bought one a while back and took it apart, I swear I had some sketches of the circuit that I found... I tried digging around for it but I have the better part of 5,000 pages of engineering paper on my bookshelf so it's like searching for a needle in a haystack. I managed to find an image that is somewhat similar to what my model had. [img]http://i.stack.imgur.com/glAS9.jpg[/img] The most notable similarities: 1. Four 1.5V batteries in series as a power source 2. The black cylinder. Upon peeling off the cover, it was a bunch of wound copper wire. I assumed that this was an inductor, but it had three contacts, not two. I was then lead to believe that it was a center tapped inductor, but that may be wrong. 3. The white circular piece. This was actually a very small PCB, and it had a large ceramic(?) blob on it, probably covering the component of interest? IIRC there were four contacts on it, two of which were attached to the batteries... (this is from memory) I found a [url=http://electronics.stackexchange.com/questions/72667/electric-chewing-gum-prank-circuit-diagram]thread on stackexchange[/url] in which a user suggested this circuit: [img]http://i.stack.imgur.com/sz0XL.png[/img] Which makes sense for the most part, but I can't figure out where the inductor(?) comes into play. I'm assuming it's the transformer in the picture, but the contacts don't add up. (3 vs. 4) Additionally, in a user in a different thread suggested [url=http://www.electro-tech-online.com/attachments/ujt-gif.465/]this circuit[/url] which is similar, but incorporates a unijunction transistor. (Additionally it's missing the switch from the first diagram, which I believe belongs between the capacitor and the Emitter terminal?) How is the function of this circuit different? Could any of you shed some light on this? Thanks in advance.

So you guys do a lot of fancy-pants programming and gizmos that I can't make, but I nearly every one puzzles me as to what purpose it serves. So here, have our machine that serves a practical and obvious purpose. [video=youtube;3WX0sasB59o]http://www.youtube.com/watch?v=3WX0sasB59o[/video]

[QUOTE=FunnyBunny;45959251] Could any of you shed some light on this? Thanks in advance.[/QUOTE] It's a regular transformer but with one side of the secondary connected to the primary, essentially making it an autotransformer since there is no longer any isolation. [img]http://upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Autotransformator_schemat.svg/333px-Autotransformator_schemat.svg.png[/img] The version with a UJT I would guess is being used similar to an SCR providing a brief output pulse once the emitter voltage rises high enough, I'm not too familiar with UJTs (they are somewhat uncommon in modern circuits) but I assume there is some current flow between B1 / B2 and the emitter, in which case the emitter capacitor will be drained partially or perhaps fully so it becomes a simple continuous pulse generator.

[QUOTE=FunnyBunny;45959251]Hey guys, this might be a bit of a rookie question because I'm still rather new to electronics, but here goes: I'm trying to figure out exactly how those "Prank Shock Gum" toys work. I actually bought one a while back and took it apart, I swear I had some sketches of the circuit that I found... I tried digging around for it but I have the better part of 5,000 pages of engineering paper on my bookshelf so it's like searching for a needle in a haystack. I managed to find an image that is somewhat similar to what my model had. [img]http://i.stack.imgur.com/glAS9.jpg[/img] The most notable similarities: 1. Four 1.5V batteries in series as a power source 2. The black cylinder. Upon peeling off the cover, it was a bunch of wound copper wire. I assumed that this was an inductor, but it had three contacts, not two. I was then lead to believe that it was a center tapped inductor, but that may be wrong. 3. The white circular piece. This was actually a very small PCB, and it had a large ceramic(?) blob on it, probably covering the component of interest? IIRC there were four contacts on it, two of which were attached to the batteries... (this is from memory) I found a [url=http://electronics.stackexchange.com/questions/72667/electric-chewing-gum-prank-circuit-diagram]thread on stackexchange[/url] in which a user suggested this circuit: [img]http://i.stack.imgur.com/sz0XL.png[/img] Which makes sense for the most part, but I can't figure out where the inductor(?) comes into play. I'm assuming it's the transformer in the picture, but the contacts don't add up. (3 vs. 4) Additionally, in a user in a different thread suggested [url=http://www.electro-tech-online.com/attachments/ujt-gif.465/]this circuit[/url] which is similar, but incorporates a unijunction transistor. (Additionally it's missing the switch from the first diagram, which I believe belongs between the capacitor and the Emitter terminal?) How is the function of this circuit different? Could any of you shed some light on this? Thanks in advance.[/QUOTE] Capacitor C1 gets charged. When you activate SW1, it releases energy from C1 (it gets discharged) through L1 transformer. Transformer transforms low voltage to high voltage (in this case), it can go other way. Transformer is basically two coils (primary and secondary) and added ferite (so magnetic force can flow more dense/easily). Transformers can have more coils but not in this case. One coil (on the left) converts electric energy into magnetic. Magnetic energy flows through ferite (it can flow through air too). On other side, magnetic force INDUCES electric energy in the coil. For voltage, it works this way: N is number of cooper wire turns. You have two Ns here. One is N1 (left), other is N2 (right). You see, the the side that has bigger N will have more voltage (V) and less amperage (A). In your case, output coil (right side of transform, N2) has more turns, and that is why it produces more voltage. Also output/secondary coil is INDUCED, that is why electricity is FORCED to flow. When electricity is FORCED to flow, and if it doesn't has anywhere to flow, the voltage (V) rises to the level where it can (this way sparks can happen). And therefore person gets shocked. Btw, big enough voltage and electricity can flow through air too, but it will always find the shortest path. Also look at this circuit [url]http://en.wikipedia.org/wiki/Joule_thief[/url] To get idea how transformers work.

[QUOTE=Oscar Lima Echo;45959374]So you guys do a lot of fancy-pants programming and gizmos that I can't make, but I nearly every one puzzles me as to what purpose it serves. So here, have our machine that serves a practical and obvious purpose. [video=youtube;3WX0sasB59o]http://www.youtube.com/watch?v=3WX0sasB59o[/video][/QUOTE] You in an elenergi class?

[QUOTE=Sombrero;45906873]My dad's friend told me his sub was working fine once a year ago and suddenly started to make a humming noise. When I would plug it in, it made a really loud (I'm almost certain it's 60hz hum) buzzing sound. When I turned the switch to a different position the noise would become much more quiet. Playing sound through it only mixed in with the hum and made weird distortion sounds. I opened it up and looked at the amp plate. I noticed the two filter caps (they were the shitty no name type) had bulged at the top. I'm suspecting those as the main offender for the noise. I noticed slight burning of the glue around the caps by a few surrounding components. The model is a mirage omni s8, and lots of people seem to have the humming problem. Do any of you think it's the caps or something else that is causing distortion and hum?[/QUOTE] I just bought this same sub with the same problem from a second hand store. did replacing the caps work? if so, can you put up pictures of where they are? thanks

Can anyone get me some good info on how to diagnose a faulty PCB? I have a PS2 power supply that wont work, I am kinda new to electronics, but i know how to handle a soldering iron and i can tell the most common electrical components apart

[QUOTE=Fatfatfatty;45970124]Can anyone get me some good info on how to diagnose a faulty PCB? I have a PS2 power supply that wont work, I am kinda new to electronics, but i know how to handle a soldering iron and i can tell the most common electrical components apart[/QUOTE] First step, got a multimeter?

[IMG_THUMB]http://i.imgur.com/BmiGnxh.jpg[/IMG_THUMB] Finally arrived! Hell yeah.

[QUOTE=Fuxed;45970270]First step, got a multimeter?[/QUOTE] Yes, I have a multimeter, figured one might be good to have if something old that i love breaks

[QUOTE=Fatfatfatty;45970124]Can anyone get me some good info on how to diagnose a faulty PCB? I have a PS2 power supply that wont work, I am kinda new to electronics, but i know how to handle a soldering iron and i can tell the most common electrical components apart[/QUOTE] Some photos would be nice too.

[QUOTE=Leestons;45970315]Some photos would be nice too.[/QUOTE] [t]https://dl.dropboxusercontent.com/u/45707598/2014-09-13%2019.43.48.jpg[/t] Should be noted that I have checked the fuse which works and all capacitors look intact and well. I am fairly sure that its the PSU that's whack cause I get no indication of power from the PS2 when its plugged into an electrical outlet which i have confirmed functional and the main power switch set to on

[QUOTE=mrmr;45970282][IMG_THUMB]http://i.imgur.com/BmiGnxh.jpg[/IMG_THUMB] Finally arrived! Hell yeah.[/QUOTE] IV 9s by the look of the writing? They are quite nice tubes, especially as they're numitrons, makes everything easy. How much did they cost, I've found that numitrons have just about doubled in price since I bought my set of IV 9s.

What's the voltage across the DC output rail leading to the PS2?

[QUOTE=LoneWolf_Recon;45970456]What's the voltage across the DC output rail leading to the PS2?[/QUOTE] Sadly have no idea, might find some technical specifications on it if i search the vast internet. Two 12V DC and two GND

Should be 12v if I remember correctly. People bypass the power supply to put them in their cars. There's the first thing for you to check. Whip out your multimeter and check your output voltage.

Would it be possible to use a computer PSU to get 12V DC to see if the main board is alright? Or am i just in for risk of electrical shock and broken PS2. Should i really test the output voltage with the thing on? Oh dear that big capacitor is scary to me. I know the bare essentials for electric safety with caps and all that.

That shouldn't be a problem providing you don't accidentally short anything.

[QUOTE=Gulen;45960092]You in an elenergi class?[/QUOTE] Automation, because there's no way I will spend my career installing outlets.

Alright, i tested the voltage, the highest reading I got was 0.05V so the PSU is probably completly buggered.

Spot on! I bought 3 packs of 6 for £9.86 each, total of £36.06 including shipping from Ukraine. It took 2 weeks just for the seller to mark it as shipped and was then delivered 3 days after the last delivery date. Taking about a month in total from ordering to having it at my desk. I'm pleased with the price I paid and I didn't really have time until now to use them, so it's worked out fine with me. You had a project that involved IV9s? Anything you can share with me? Tips/Advice?

[QUOTE=ben1066;45970451]IV 9s by the look of the writing? They are quite nice tubes, especially as they're numitrons, makes everything easy. How much did they cost, I've found that numitrons have just about doubled in price since I bought my set of IV 9s.[/QUOTE] Bought about 36 for a thing I'm doing a week or two back and paid €3,- a piece, could have probably gotten them cheaper but I needed them quick. [editline]13th September 2014[/editline] Oh and this thing again: [url=http://i.imgur.com/W7MwNmI.jpg][img]http://i.imgur.com/W7MwNmIl.jpg[/img][/url]

[QUOTE=mrmr;45970600]Spot on! I bought 3 packs of 6 for £9.86 each, total of £36.06 including shipping from Ukraine. It took 2 weeks just for the seller to mark it as shipped and was then delivered 3 days after the last delivery date. Taking about a month in total from ordering to having it at my desk. I'm pleased with the price I paid and I didn't really have time until now to use them, so it's worked out fine with me. You had a project that involved IV9s? Anything you can share with me? Tips/Advice?[/QUOTE] I didn't do anything too fancy. I was running them off a 74HC595, which is out of spec I believe, at 3.3V and they ran just fine. I could also use PWM on the enable line to give some brightness adjustment but it was limited as too low of a duty cycle resulted in the tubes being completely off. They are fun tubes to play with though and are probably the reason I've now got some VFDs to play with.

[QUOTE=Fatfatfatty;45970594]Alright, i tested the voltage, the highest reading I got was 0.05V so the PSU is probably completly buggered.[/QUOTE] Most likely, without a proper schematic it's a pain to diagnose boards (and board tracing is a bitch to do). Since you've got the "Fat" PS2 model, the PC PSU 12V should do the trick for a hacky solution. I'd recommend checking to see which lines on the connector from the power supply -> main board are connected. According to [URL="http://nfggames.com/forum2/index.php?topic=1115.0"]a[/URL] [URL="http://forums.modretro.com/viewtopic.php?f=64&t=11962"]few[/URL] sources: There should be four lines, two are 12V and two are Ground, some saying the current draw on the 12V line can be as high as 8 Amps, so double check your PSU can supply that on the 12V rail.

[QUOTE=Oscar Lima Echo;45970571]Automation, because there's no way I will spend my career installing outlets.[/QUOTE] Ah, same as I'm supposed to do, then. Which year are you in?

[QUOTE=LoneWolf_Recon;45971290]Most likely, without a proper schematic it's a pain to diagnose boards (and board tracing is a bitch to do). Since you've got the "Fat" PS2 model, the PC PSU 12V should do the trick for a hacky solution. I'd recommend checking to see which lines on the connector from the power supply -> main board are connected. According to [URL="http://nfggames.com/forum2/index.php?topic=1115.0"]a[/URL] [URL="http://forums.modretro.com/viewtopic.php?f=64&t=11962"]few[/URL] sources: There should be four lines, two are 12V and two are Ground, some saying the current draw on the 12V line can be as high as 8 Amps, so double check your PSU can supply that on the 12V rail.[/QUOTE] Seems like my spare PSU has fucked off to godknowswhereville. Gonna have to get some croc clips and some wire and something to connect to my PSU with in case it shows up again. And one more little question, having too low ampage wouldnt hurt the PS2 would it?

[QUOTE=ddrl46;45970751]Bought about 36 for a thing I'm doing a week or two back and paid €3,- a piece, could have probably gotten them cheaper but I needed them quick. [editline]13th September 2014[/editline] Oh and this thing again: [url=http://i.imgur.com/W7MwNmI.jpg][img]http://i.imgur.com/W7MwNmIl.jpg[/img][/url][/QUOTE] That's really pretty.

I tried to record my laser this evening, the ambient light was still kinda odd though. The "canvas" is a forest about ~25m away from where I recorded. [vid]http://luastoned.com/laser_v2.mp4[/vid]

Have you tried using the laser with a long exposure photograph? Seems like the perfect fit.

Don't know if it's relevant for this thread, but I've been messing with an Arduino + ethernet shield, and got it to read txt files from the on-board sd slot and then put the data up online. It seems to work just as I want, and succesfully uploads HTML. It's way easier than I ever though it'd be :v: