Electrical Engineering V2 - Developers

[QUOTE=Van-man;42808904]Li-ion cells are typically "battery" shaped, while li-poly most of the time are "pouches" Generally li-ion cells are more durable though. Try and look for li-ion battery packs based on 18650 cells that's mean for R/C applications. You'd probably need to buy two 4-cell packs and putting them in series. Most other packs have protective circuitry that isn't fond of such short but high-current loads. That fuckin' motor looks EXACTLY like the one i ripped out of a beefy cordless drill where the casing and battery were trashed.[/QUOTE] Yeah those motors are very common in drills and those terrible air compressors you find at the dollar/euro/pound stores, I have a few laying around as well.

[QUOTE=ddrl46;42808004] [url=http://i.imgur.com/pDAoCG7.jpg][img]http://i.imgur.com/pDAoCG7l.jpg[/img][/url][/QUOTE] I'm getting one of these myself for Christmas, a must have if you desolder a lot of stuff. £78 from CPC.

Ddrl, why the hell are desoldering stations cheaper for you?

[QUOTE=pentium;42810707]Ddrl, why the hell are desoldering stations cheaper for you?[/QUOTE] Atleast it counters what everyone else has to pay for the FX-888 220V.

Okay kids, lets play a game of "what the fuck IS this thing!" Today we have some sort of detection device, manufactured by Fredrick Goertz Ltd. Of Vancouver BC. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0427.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0430.jpg[/IMG] Contains very little. Only the space for an obsolete battery, two wax capacitors, a mica capacitor, a resistor, a Raytheon tube that can only identified as having a C in the model and a three position rotary knob along with a pair of plugs to attach headphones. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0428.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0429.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_0431.jpg[/IMG] I'd guess a Geiger counter but would expect more. There's just nothing inside it.

Did you try turning it on?

[QUOTE=DrDevil;42823550]Did you try turning it on?[/QUOTE] It needs one of those oddball batteries like an A or B cell which gives out 80 volts or something weird. I've never seen one myself. They don't make them anymore either.

It [URL="http://www.badcaps.net/forum/showthread.php?p=51512"]is[/URL] a Geiger counter.

Holy shit. I forgot about that thread.

I want a really simple way to generate about 400v. Bear with me - but would ripping the transformer from a 5v mobile phone charger and running it in reverse powered by a 9v battery do the trick, or is something likely to melt?

[QUOTE=chaz13;42827987]I want a really simple way to generate about 400v. Bear with me - but would ripping the transformer from a 5v mobile phone charger and running it in reverse powered by a 9v battery do the trick, or is something likely to melt?[/QUOTE] transformers only work with AC, with DC they'd definetly just melt.

[QUOTE=Van-man;42828005]transformers only work with AC, with DC they'd definetly just melt.[/QUOTE] Oh my bad, I mean running it +-9v using a 555 timer or something.

[QUOTE=chaz13;42828043]Oh my bad, I mean running it +-9v using a 555 timer or something.[/QUOTE] It would be possible, but it depends on so many factors.

Depending on the currents you need, you could use a voltage multiplier. It's the easiest way to achieve your goal in a safe and controllable manner.

Thanks for the help! I've been doing some research today on this, and I've come up with this circuit: [img]http://i.imgur.com/hElDTn3.png[/img] Does it look like it might do the job? the stage before the transformer is supposed to take a 12v battery and output ac to the transformer, the second stage is just a full wave rectifier. [QUOTE=DrDevil;42828309]Depending on the currents you need, you could use a voltage multiplier. It's the easiest way to achieve your goal in a safe and controllable manner.[/QUOTE] I checked them out, would definitely be simpler but I think I'd need a 10 stage multiplier which seems a bit large, but then gain.. maybe!

[QUOTE=chaz13;42831946] I checked them out, would definitely be simpler but I think I'd need a 10 stage multiplier which seems a bit large, but then gain.. maybe![/QUOTE] Not really, just need some extra diodes and caps.

What would be a good basis for a custom carputer? I've been looking at the R-Pi but I've been told it's a rather wonky piece of work for that goal as it has no ACPI. Also; I want to figure out how to work with parking sensors, y'know those ultrasonic ones. How would I go about finding out how they work and how I can implement them in my own things?

A little bit of advice guys particularly if you have a Rigol, always always check the software attenuator settings, I just spent the last 45 minutes wondering why my amplifier has no gain. [img]http://www.paulhebble.net:8000/Rage-Guy-Face.png[/img] Also I've discovered you can build perfectly usable tube amplifier with as little as 9V, although it will distort more than usual.

[QUOTE=chaz13;42831946][...] I checked them out, would definitely be simpler but I think I'd need a 10 stage multiplier which seems a bit large, but then gain.. maybe![/QUOTE] May I recommend a ZVS driver? [IMG]http://uzzors2k.4hv.org/projectfiles/flybacktransformerdrivers/Mazzilli%20ZVS%20Flyback%20Driver.png[/IMG]

[QUOTE=LoneWolf_Recon;42836328]May I recommend a ZVS driver? [IMG]http://uzzors2k.4hv.org/projectfiles/flybacktransformerdrivers/Mazzilli%20ZVS%20Flyback%20Driver.png[/IMG][/QUOTE] Those things can be rather unstable to be honest, try making a half-bridge driver off-line from mains driving a old flyback core with 50 turns or so primary and 87 turns on secondary should give you ~400v. or you could look through the datasheets i uploaded here: [url]https://mega.co.nz/#!uQ4GgaYJ!PW6GUgprNKyvWMADXR_WyU3_WRR9UTua3K5Xvlp9jGo[/url] They are all application notes and such from various IC and power semiconductor manufacture ( really interesting read, i learn a lot from these things ) Theres quite a lot of them in there. the 2.5Kw switchmode PSU is very interesting too! I would reccomend taking one of the designs from there and modifying it to your own needs, if you feel a half-bridge is too powerful or complex for you, i would seriously try doing a boost converter! Have fun!

[QUOTE=Chryseus;42832609] Also I've discovered you can build perfectly usable tube amplifier with as little as 9V, although it will distort more than usual.[/QUOTE] That distortion is perfect good sir.

Thanks guys! Much appreciated as always :smile:

Fun RF times [img]http://i.imgur.com/PjIYfN6.png[/img]

What op-amps are both cheap and still decent enough to dick around with in Audio related projects? [URL="http://www.taydaelectronics.com/ic-integrated-circuits/audio-amplifier-instrumentation-op-amp.html?limit=all"]After all, the prices wary wildly[/URL]

[QUOTE=Van-man;42838848]What op-amps are both cheap and still decent enough to dick around with in Audio related projects? [URL="http://www.taydaelectronics.com/ic-integrated-circuits/audio-amplifier-instrumentation-op-amp.html?limit=all"]After all, the prices wary wildly[/URL][/QUOTE] What do you define as decent? You could easily use any run of the mill LMxxx opamp for audio stuff, and those are pretty much almost free.

[QUOTE=DrDevil;42839032]What do you define as decent? You could easily use any run of the mill LMxxx opamp for audio stuff, and those are pretty much almost free.[/QUOTE] Around the same quality of a average modern smartphone.

So, most likely any jellybean op-amp would do, but I'm sure somebody else in here will have more experience than me.

Whoo! my new toys got here. ...I forgot headers.

[QUOTE=S31-Syntax;42839181]Whoo! my new toys got here. ...I forgot headers.[/QUOTE] Go buy one of those 1000-packs of headers on ebay. I bought mine 3 years ago and I still didn't run out.