My Website with electronics Info - Page 1
Forum section: electronics / general

author: MONODA
author_rank: Contributor
timestamp: May 23, 2013, 03:10:31 pm
content: Hey guys, a couple of months back, me and a friend of mine were wondering why there aren't any websites that give explanations to interesting scientific phenomena and mathematical topics so we decided to make out own.At first we made a list of interesting questions that most people wonder but often can't find a good explanation to. This quickly evolved into a wiki where people can improve explanations and can discuss the topic in a related discussion tab at the top of the page. Some of the questions include:What is slipperier, smooth or bumpy ice?Why is text in a mirror flipped horizontally but nor vertically?Why do we only see one side of the moon from Earth?How can airplanes fly upside down?We then decided to add a Projects section where people can make a page about a project they are working on and describe the process and some of the things they learned and had trouble with. We also added discussion pages here so that people can comment on each others projects and give advice and ask questions.What is appealing to me about this is that it gives people a chance to see how others approach solving problems with their project and also gives others a chance to give the poster advice on how to fix the issue they are having.Thus far, we've only posted about a bench top power supply that we've been working on. Since we are both undergrads, it's difficult to find time to add content AND work on the project itself.Check it out!http://www.turtleneckhub.com/Oh, and can you guess where we got the name from?

author: free_electron
author_rank: Super Contributor
timestamp: May 23, 2013, 03:56:39 pm
content: because your necks are wrinkeled and flabby ?wolfram alpha ?

author: free_electron
author_rank: Super Contributor
timestamp: May 23, 2013, 04:46:51 pm
content: I just lost my breakfast and was at the point of gauging my eyes out. Will you please remove that horrible power supply schematic and that disaster of a PCB layout. You are polluting the internet. That thing can't even be labeled 'designed by monkeys'. It would have to carry the label 'End result of shoveling together the byproduct of some bovines that suffer from chronic diarrhea , wallowed in by a bunch of mud-dwellers...'

author: MONODA
author_rank: Contributor
timestamp: May 23, 2013, 07:54:54 pm
content: It could definitely be neater but the goal of the layout was to separate the heat dissipating components from the capacitors. Also, its a single sided board so I needed to place quite a few jumpers.Anyway, this is exactly the point of this website, for people to talk about what is wrong with the designs etc. Go ahead and write whatever comments you want (within reason). You don't even need to make an account to edit.

author: ddavidebor
author_rank: Super Contributor
timestamp: May 23, 2013, 08:41:55 pm
content: Quote from: free_electron on May 23, 2013, 04:46:51 pmYou're trolling a bit... But you're right... It's one of the worst i've ever seen.

author: free_electron
author_rank: Super Contributor
timestamp: May 23, 2013, 10:36:05 pm
content: heat is the least of your worries....layout : parts are in totally wrong places , wrong footprints , wrong tracewidths ,schematic : no local bypass caps, no backfeed diodes , no output reversal protection , no output buffer caps. and those four poor 1 ampere diodes are going to commit suicide once you load some of your regulators... and what's up with that 1 meg resistor. and what with the potmeter. if you dial that potmeter to 0 you apply -12 volt to the adjust pin of the lm117 ... that thing is going to reach for the stars. let alone the 560 ohm resistor that will emit smoke signals ....these kind of schematics give a bad example for people that want to learn somethingclean it up.you can easily make a nice supply with fixed 5 -5 +12 and -12 and two adjustables on half the pcb size , single sided without solder bridges or wires.if i got a moment i will whip up a schematic.

author: c4757p
author_rank: Super Contributor
timestamp: May 23, 2013, 10:44:01 pm
content: Oh my god! What happened tothat PCB?Somebody alert the humane society, copper clad boards are being tortured!QuoteNowthisI want to see.

author: c4757p
author_rank: Super Contributor
timestamp: May 23, 2013, 10:55:25 pm
content: Quote from: free_electron on May 23, 2013, 10:36:05 pmCMIIW, but... -12V on the LM117 adjust pin. 117 maintains 1.25V between adj and out, giving 2.2mA in the 560 ohm resistor and -10.75 on the output...? I'm pretty sure about that. Just to check, hmm... yep, LTspice seems to agree.It's a bizarre and useless contraption, but I don't think anything is going to emit smoke signals.(For what it's worth, that LM317 model - from TI, if I remember right - is often bizarrely and hilariously incorrect when you don't use it in the usual way, but again I was already pretty sure before the sim.)

author: MONODA
author_rank: Contributor
timestamp: May 23, 2013, 11:04:04 pm
content: The 1 meg resistor is only a load because the simulation with Multisim wouldn't converge without a load on the output. Also, the transformer I am using is rated at 1 amp on the secondary so I've designed the rest with that in mind. Shouldn't that work fine?Also, I've redone the layout. This time double sided, but I limited the number of traces on the other copper layer.

author: c4757p
author_rank: Super Contributor
timestamp: May 23, 2013, 11:06:12 pm
content: Quote from: MONODA on May 23, 2013, 11:04:04 pmWhat do you think keeps you from drawing more than that and blowing the ass out of something?

author: MONODA
author_rank: Contributor
timestamp: May 23, 2013, 11:08:43 pm
content: Haha, I've placed a 1A fuse in series with the secondary of the transformer.

author: c4757p
author_rank: Super Contributor
timestamp: May 23, 2013, 11:12:22 pm
content: Make sure you build a nice big tray into the enclosure to hold a pile of replacement fuses.

author: lemmegraphdat
author_rank: Frequent Contributor
timestamp: May 23, 2013, 11:18:22 pm
content: This right here is my most favoritest thread thus far.

author: Daniyal
author_rank: Contributor
timestamp: May 24, 2013, 02:44:58 pm
content: I agree