Electrical Engineering V2 - Developers

[QUOTE=Chryseus;43035567]Look on the German ebay, you should be able to get a local supplier easy enough. Assuming flagdog is correct of course.[/QUOTE] Right, didn't think of that, thanks. Now shipping is free.

[QUOTE=nutcake;43035770]Right, didn't think of that, thanks. Now shipping is free.[/QUOTE] Nusskuchen I have this one: [url]http://www.ebay.de/itm/Labornetzgerat-0-30V-5A-150W-Netzgerat-Trafo-Labornetzteil-Netzteil-regelbar-/400526573101?pt=Netzger%C3%A4te&hash=item5d413e7e2d[/url] And for the price it does a very decent job. A minor annoyance is that it has no carrying handle on the top. Other than that the voltage display is pretty precise and the voltage goes up to 34V and the current up to 3.2A (although I didn't test 3.2A @ 34V yet, might be unstable). On the inside it has a nice toroid transformer, so it's not heavy as heavy as a stack of bricks. The Fan is temperature controlled, and is very quiet. Together with the beefy heatsink it only turns on if you go into higher wattages. The knobs are a bit spongy, but for that pricetag it's ok. You get fine and coarse control, where the fine is really fine, you can precisely set the voltage and current. Pics from the insides: [t]http://i.imgur.com/708bmgo.jpg[/t] [t]http://i.imgur.com/CFFqsTh.jpg[/t] [t]http://i.imgur.com/2wYJIzn.jpg[/t] [t]http://i.imgur.com/veYMtP2.jpg[/t] Rubycon decoupling caps, beauty!

[QUOTE=DrDevil;43036404] Rubycon decoupling caps, beauty![/QUOTE] I wouldn't count on those being genuine Rubycon :v:.

[QUOTE=ddrl46;43036691]I wouldn't count on those being genuine Rubycon :v:.[/QUOTE] I don't think so. For 70€ you can expect them to be real.

I really should get myself a power supply but if I remember correctly they cost a small fortune

[QUOTE=DrDevil;43036404]Nusskuchen I have this one: [url]http://www.ebay.de/itm/Labornetzgerat-0-30V-5A-150W-Netzgerat-Trafo-Labornetzteil-Netzteil-regelbar-/400526573101?pt=Netzger%C3%A4te&hash=item5d413e7e2d[/url] And for the price it does a very decent job. A minor annoyance is that it has no carrying handle on the top. Other than that the voltage display is pretty precise and the voltage goes up to 34V and the current up to 3.2A (although I didn't test 3.2A @ 34V yet, might be unstable). On the inside it has a nice toroid transformer, so it's not heavy as heavy as a stack of bricks. The Fan is temperature controlled, and is very quiet. Together with the beefy heatsink it only turns on if you go into higher wattages. The knobs are a bit spongy, but for that pricetag it's ok. You get fine and coarse control, where the fine is really fine, you can precisely set the voltage and current. Rubycon decoupling caps, beauty![/QUOTE] [URL="http://www.ebay.de/itm/0-30V-3A-3AMP-Digital-DC-Power-Supply-Lab-Precision-Variable-110-220V-Adjustable-/131021090710?pt=LH_DefaultDomain_0&hash=item1e81772f96"]This one[/URL] is half the price, it's one of the ones that Chryseus posted, and I don't really see any big differences. Obviously one might have more expensive internals but I don't know that and in all honesty, I don't care how "clean" and "interference free" the energy coming out of it is (yet) as long as it's stable. :v:

[QUOTE=nutcake;43036841][URL="http://www.ebay.de/itm/0-30V-3A-3AMP-Digital-DC-Power-Supply-Lab-Precision-Variable-110-220V-Adjustable-/131021090710?pt=LH_DefaultDomain_0&hash=item1e81772f96"]This one[/URL] is half the price, it's one of the ones that Chryseus posted, and I don't really see any big differences. Obviously one might have more expensive internals but I don't know that and in all honesty, I don't care how "clean" and "interference free" the energy coming out of it is (yet) as long as it's stable. :v:[/QUOTE] The cheaper ones can have really nasty problems that could fry your circuits. For example, the one ddrl owns has a 1V spike when it's turned off. If you power a 3.3V circuit with it, that could very well fry it. Also, cheapos often have fake capacitors for mains decoupling, which could end up in your PSU failing soon, and there might be considerable output voltage-ripple. Trust me, with a Lab-PSU you can't do any wrong by spending 20€ more on it. Also the one you linked has 70$ shipping cost, hardly any cheaper.

[QUOTE=DrDevil;43036947]The cheaper ones can have really nasty problems that could fry your circuits. For example, the one ddrl owns has a 1V spike when it's turned off. If you power a 3.3V circuit with it, that could very well fry it. Also, cheapos often have fake capacitors for mains decoupling, which could end up in your PSU failing soon, and there might be considerable output voltage-ripple. Trust me, with a Lab-PSU you can't do any wrong by spending 20€ more on it. Also the one you linked has 70$ shipping cost, hardly any cheaper.[/QUOTE] For me it says free shipping but w/e, that shit sounds horrible so I'll go with the one you posted then.

[QUOTE=DrDevil;43034098]try to not tape it on solid like that. I've dismantled a few items with piezoelectric transducers, and they all were mounted using a round sticky rubberseal only.[/QUOTE] Actually it has three spots of hot glue. The tape just prevents the wire from snagging on the electronics when the base is latched on. I'll try it again though with a gap. Edited: Worked better after I bypassed a resistor. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0456.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0457.jpg[/IMG]

So this was the final product of me and my teammates final project for one of our engineering classes. A greenhouse control system that regulates light and temperature levels based on a basic hysteresis algorithm. Arduino controlled, NiMH powered, Solar Recharging, Window Blockage Detection, and more. [img_thumb]https://scontent-b-iad.xx.fbcdn.net/hphotos-ash4/1462985_10202640153194692_1209413538_n.jpg[/img_thumb] Only problem remained with the solar cells, I put them in series to bump up the voltage to trickle charge, however due to imperfections and differences in both cell's MPPT's they had a lousy output current (~3mA together, compared with ~12mA alone), thus the charge time was 1100 hours from deep discharge to peak. Oh well, good proof of concept.

How do you find shorts in a circuit? My Galaxy Note went dead a couple of months ago, so i took it and thought i'd have a look what's wrong with it. I started from measuring the off ( dead phone that doesn't even boot ) current. To my surprise, it was 0 along with the voltage 0. That meant that the battery protection circuit was kicking in to protect it from shorts. Checked the phone's power supply contacts and those appear to be shorted. EDIT: I'm thinking of slamming a few amps through the phone incase its a bad cap so it gets blown off the board.

[QUOTE=alexaz;43056014]How do you find shorts in a circuit? My Galaxy Note went dead a couple of months ago, so i took it and thought i'd have a look what's wrong with it. I started from measuring the off ( dead phone that doesn't even boot ) current. To my surprise, it was 0 along with the voltage 0. That meant that the battery protection circuit was kicking in to protect it from shorts. Checked the phone's power supply contacts and those appear to be shorted. EDIT: I'm thinking of slamming a few amps through the phone incase its a bad cap so it gets blown off the board.[/QUOTE] Why don't you throw it under a car aswell? Maybe that will shake a few other unecessary components off.

i dont want to scratch the screen

[QUOTE=alexaz;43056014]How do you find shorts in a circuit? My Galaxy Note went dead a couple of months ago, so i took it and thought i'd have a look what's wrong with it. I started from measuring the off ( dead phone that doesn't even boot ) current. To my surprise, it was 0 along with the voltage 0. That meant that the battery protection circuit was kicking in to protect it from shorts. Checked the phone's power supply contacts and those appear to be shorted. EDIT: I'm thinking of slamming a few amps through the phone incase its a bad cap so it gets blown off the board.[/QUOTE] I'm no qualified engineer, but I can straight-up tell you that putting a butt-load more current than your device can handle is NOT the proper way to find a short. Unless you just want to explode all the fine wires in your phone's board, as well as blow nearly every resistor, capacitor, diode, etc. at the same time, then by all means, shove "a few amps" through it.

I wonder if its possible to make a transistor equivalent (solid state) without using doped silicon. Cause I really wanna make transustors at home but getting the right doping in the right places requires weird chemicals and a good oven...

[QUOTE=DrDevil;43036404]Nusskuchen Rubycon decoupling caps, beauty![/QUOTE] Dave Jones.

[QUOTE=Nikita;43065894]I wonder if its possible to make a transistor equivalent (solid state) without using doped silicon. Cause I really wanna make transustors at home but getting the right doping in the right places requires weird chemicals and a good oven...[/QUOTE] Yes it is possible to make a transistor using point contact methods although the performance you'll get is absolutely awful compared to any modern transistor, there isn't really any easy method as far as I'm aware to make transistors. You'd probably have more luck making vacuum tubes, although that of course requires a vacuum pump.

[QUOTE=birkett;43065922]Dave Jones.[/QUOTE] Well, you found out my true identity

Ok so I've been pulling the pieces off my old DVR that apparently my provider doesn't know about. I found this! Please excuse the shoddy picture, I'm having the shakes. [thumb]http://i.imgur.com/2qLgu6M.jpg[/thumb] Any cool shit I could pull off with this?

[QUOTE=Nightrazr;43066381]Ok so I've been pulling the pieces off my old DVR that apparently my provider doesn't know about. I found this! Please excuse the shoddy picture, I'm having the shakes. [thumb]http://i.imgur.com/2qLgu6M.jpg[/thumb] Any cool shit I could pull off with this?[/QUOTE] Those pushbuttons could be useful, the display *may* be useful (You'll most likely have to fiddle with the pins as part numbers on these things are rare and are typically in-house parts), the crystal oscillator could be useful, the IR receiver should be useful and some of those chips (If you can find what they are) could be useful

[QUOTE=LoneWolf_Recon;43066435]Those pushbuttons could be useful, the display *may* be useful (You'll most likely have to fiddle with the pins as part numbers on these things are rare and are typically in-house parts), the crystal oscillator could be useful, the IR receiver should be useful and some of those chips (If you can find what they are) could be useful[/QUOTE] Cool beans, time to haul this crap to the soldering station.

in 99.999% of cases you won't find the datasheet for displays you pull out of electronics. The only way to operate it is to reverse engineer it while it's still in the circuit, but that often simply isn't worth the effort.

[QUOTE=DrDevil;43066472]in 99.999% of cases you won't find the datasheet for displays you pull out of electronics. The only way to operate it is to reverse engineer it while it's still in the circuit, but that often simply isn't worth the effort.[/QUOTE] Nor something I am capable of doing yet. I'll just go rip the caps n shit out of the DVR, see what I can mess with.

[QUOTE=Nightrazr;43066490]Nor something I am capable of doing yet. I'll just go rip the caps n shit out of the DVR, see what I can mess with.[/QUOTE] Well since this isn't one of those VFDs that has the driver integrated inside of the display itself it shouldn't be too hard to figure out how to drive it really, on some of them it's even possible to see what goes where on the back side of the thing.

The back is transparent and there's a sticker that gives me a model name I'll go and write it down.

Woop, my ATXMega128A3 arrived, now I can finally enjoy 7 serial ports, 4 i2c interfaces, and 3 spi interfaces, aswell with a shitton of other peripherals (including a 12-bit DAC and ADC). In short, this mcu is pretty badass.

24 down... [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_4003.jpg[/IMG] ...a whole lot more to go. Edited: Oh my god that sucked so much. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0482.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0485.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0486.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0487.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0488.jpg[/IMG]

That looks like a short circuit waiting to happen.

That looks like modern art. It's beautiful.

[QUOTE=pentium;43073043]24 down... [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_4003.jpg[/IMG] ...a whole lot more to go. Edited: Oh my god that sucked so much. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0482.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0485.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0486.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0487.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CGS_0488.jpg[/IMG][/QUOTE] Have fun hunting around for the other side of the wire then forgetting it when you go to solder it on and soldering on the wrong wire (i do that a lot)