[QUOTE=Leestons;48043857]If I didn't already have a PSU I would make one out of a computer power supply.[/QUOTE]
They're pretty commonplace & robust though, even when finding beat up old PCs in the trash you can salvage a decent still functioning PSU.
[QUOTE=LoneWolf_Recon;48043877]They're pretty commonplace & robust though, even when finding beat up old PCs in the trash you can salvage a decent still functioning PSU.[/QUOTE]
They're great, I just don't have a need for one. If I didn't have my 0-30V 0-5A PSU I'd go and make an ATX bench power supply.
Just protect the outputs or something like that, last time I shorted one out by accident it didn't go into over current protection and kept happily pumping all of its juice through a wire till started smoking.
[QUOTE=ddrl46;48044121]Just protect the outputs or something like that, last time I shorted one out by accident it didn't go into over current protection and kept happily pumping all of its juice through a wire till started smoking.[/QUOTE]
I had one sort of do that when I plugged in a floppy drive some years back. Burned ALL the insulation off of the wires going into it in seconds (but it stopped once it reached the next molex connector) and, of course, copious amounts of magic smoke. The kind of amount that, when inhaled fully, could literally grant you magical powers*. No idea why the hell that drive caused that.
*or at least you would be convinced you had magical powers right up until you died
Could someone help me understand something a little better? If I use a capacitor consisting of 10 alternating plates, does that mean I'm using 5 capacitors in series or parallel within? It seems smarter that they'd be parallel but the wording makes it seems like it's in series.
Alternating plates is just 5 capacitors in series. Assuming you're physically stacking the plates (between each dielectric mind you) in a row.
[QUOTE=LoneWolf_Recon;48049405]Alternating plates is just 5 capacitors in series. Assuming you're physically stacking the plates (between each dielectric mind you) in a row.[/QUOTE]
The case I was given used a glass dielectric so it made more sense they were physically stacked, yes. But in the case of an air-core capacitor it seems safe to assume it's in parallel then seeing as you can't suspend a plate in mid air?
And what advantage does that have against them being in parallel in general? I'm stuck between two ideas: If something happens internally and one plate is destroyed completely, the whole capacitor is done and you won't be able to withstand any faults. But at the same time you could just completely avoid this by wiring a second capacitor, and it's much easier to replace the whole capacitor component rather than an internal component.
Little bit correction on my part, it also depends upon how you wire the plates. If you're just physically stacking them in a row and none of the plates (except for the two end plates) are connected to VCC/GND, then they're in series.
The aircore is still in series at that point.
Parallel vs Series is something you'll have to consider depending upon the application. The main differences are:
Parallel sums the capacitance together, but each capacitor is still charged to the same voltage potential (This is if you want a unified capacitor bank with lotsa charge).
Series sums the reciprocal of all capacitors (1/C_total = 1/C_1 + 1/C_2 ....), but you can then stack lower working voltage capacitors together to work at a higher voltage.
Also, what voltage are you working this proposed air cap at & what is the application? The dielectric breakdown for air is 3 x 10^6 V/m.
[QUOTE=Ithon;48037698][url]http://www.goldmine-elec-products.com/prodinfo.asp?number=G17365[/url]
5 dollar Geiger tube, expires tomorrow, it's like at steam sale price.[/QUOTE]
Really annoys me that they don't ship to the UK :(
EDIT: That said... geiger tubes seem reasonably cheap from Ukraine or Bulgaria on ebay here... might pick one up to add to my collection of old tubes to try and use...
[QUOTE=ben1066;48056949]Really annoys me that they don't ship to the UK :(
EDIT: That said... geiger tubes seem reasonably cheap from Ukraine or Bulgaria on ebay here... might pick one up to add to my collection of old tubes to try and use...[/QUOTE]
Got the exact same tube for like 3 dollars including shipping off of ebay a while ago. Not a good deal at all to be honest.
[QUOTE=Trebgarta;48057176]Might wanna get into this.
How are these two books?
[url]http://www.amazon.com/gp/product/0071771336/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER[/url]
[url]http://www.amazon.com/Make-Electronics-Discovery-Charles-Platt/dp/0596153740/ref=pd_sim_14_1?ie=UTF8&refRID=0NH7DTCGQZHZE0SKJWYW[/url]
I want to get them, but they'll cost an arm and will get here in 2 weeks, so I wanna ask as much as I can before I place an order or something. Whyever I can't trust the amazon comments.[/QUOTE]
There are a lot of books, video tutorials and other stuff available online for free if you look around, there is also some stuff in the op.
If you really want a physical book I suggest:
Getting Started in Electronics by Forrest Mims
Great books with tons of illustrations, really easy to read.
Principles of Electric Circuits by Thomas L. Floyd.
A very good book for a more in depth introduction to electronics, has quizzes and such which is really handy.
If you want electronics books on a budget you might want to get them from India, they are massively cheaper and just as good quality.
[QUOTE=ben1066;48056949]Really annoys me that they don't ship to the UK :(
EDIT: That said... geiger tubes seem reasonably cheap from Ukraine or Bulgaria on ebay here... might pick one up to add to my collection of old tubes to try and use...[/QUOTE]
The SI-3BG isn't a particularly sensitive tube, SBM-20 is generally a better choice unless your trying to measure something highly radioactive.
[QUOTE=Chryseus;48058262]There are a lot of books, video tutorials and other stuff available online for free if you look around, there is also some stuff in the op.
If you really want a physical book I suggest:
Getting Started in Electronics by Forrest Mims
Great books with tons of illustrations, really easy to read.
Principles of Electric Circuits by Thomas L. Floyd.
A very good book for a more in depth introduction to electronics, has quizzes and such which is really handy.
If you want electronics books on a budget you might want to get them from India, they are massively cheaper and just as good quality.
The SI-3BG isn't a particularly sensitive tube, SBM-20 is generally a better choice unless your trying to measure something highly radioactive.[/QUOTE]
Yeah I did some reading, might get an SBM-20 or similar tube to try and use, I don't really have any reason to have a geiger tube, other than wanting too. Would be kinda cool to have a counter using one of the VFDs I bought and one of these tubes or something.
[QUOTE=ddrl46;48057951]Got the exact same tube for like 3 dollars including shipping off of ebay a while ago. Not a good deal at all to be honest.[/QUOTE]
Yeah I realised they were super cheap when I looked on eBay.
I got a new toy!
[t]http://i.imgur.com/QhtVHqe.png[/t]
This thing is actually not bad. I'd call it the baofeng of the mobile radio world. Right now I have it powered from my power supply so I can program it but it'll be taking up residence in my vehicle for both work and amateur use.
my 2100 resistors came in the mail!
...
not sure what I can do with them.
I'm still waiting on my 50 tip120 transistors
I just ordered 2 transcievers, a gyro, an arduino and some misc materials. I didn't do anything electrical engineering related in a long time so as a comeback i decided why not build a computer controlled quadcopter!
The control software would be written in C#, it would control the thing wirelessly. The arduino would just contain a basic program that would parse input from the computer.
Hopefully didn't forget to buy anything, it's $40 worth of materials. Well if i'll be missing something i can almost guarantee i can find it somewhere in the house.
[editline]27th June 2015[/editline]
Oh yeah, that would also be the first time i'm working with an arduino.
[QUOTE=cartman300;48060919]
Oh yeah, that would also be the first time i'm working with an arduino.[/QUOTE]
Arduino is nice and easy, I don't think you'll have much difficulty with it.
Are there any EE books or online tutorials that cover things from more of a physics perspective? A lot of the stuff I was learning in those starter books didn't make any sense until I took physics classes, but it seems like all of the EM classes offered here past the introductory ones stray really far from EE. Some of the physics books my uni used also tend to skip over bits of detail in order to cover as much information as possible in a short amount of time.
As it is, I hardly understand why voltage looks the way it does when a voltage source is connected in series with two resistors of different values. Basic voltage distribution and ohm's law are always taught in a very empirical way with lots of analogies. I know what happens, I can do the math, and I know how to do more advanced circuit stuff than that, I just don't know where those mathematical models really come from. I've only found a couple of documents that talk about the microscopic reasoning behind it.
[QUOTE=papkee;48059714]I got a new toy!
[t]http://i.imgur.com/QhtVHqe.png[/t]
This thing is actually not bad. I'd call it the baofeng of the mobile radio world. Right now I have it powered from my power supply so I can program it but it'll be taking up residence in my vehicle for both work and amateur use.[/QUOTE]
Nah, the Baofeng of the mobile world is [url=http://www.ebay.ca/itm/QYT-KT8900-136-174-400-480MHz-dual-band-Mini-Mobile-Radio-KT-8900-Transceiver-/201375943189?pt=LH_DefaultDomain_0&hash=item2ee2f10a15]one of these[/url], it uses the same chipset (with a bigger PA stage) as a baofeng.
I'm not sure if this is the right place for my question, but i figured you guys might know the answer.
My mom dropped her Nokia Lumia 830 in water at work. Some weeks have passed and the phone remains dead (no visible damage/corrosion inside). I have the same phone so i did some testing and now know that it's just the logic board that needs replacing.
I know it's pricey but i'm looking to buy a new one online (or a phone with a cracked screen or something).
I'm wondering what this IMEI thing is though. What does it mean when it's clean?
I thought that perhaps they aren't locked to a provider (like AT&T) then, but that doesn't seem to be the case.
Edit:
So all the IMEI does is allow/block the phone's access to the network to prevent theft and things like that?
Or am i wrong about this?
Yes, IMEI is an identification number for phones, sort of like a serial number and if your phone is stolen you can use it to have your provider lock the phone
[QUOTE=Goz3rr;48063167]Yes, IMEI is an identification number for phones, sort of like a serial number and if your phone is stolen you can use it to have your provider lock the phone[/QUOTE]
I see.
Would AT&T unlock my board if i send a request? I don't really have any experience with locked phones but i found some good board's online all being AT&T locked.
I know there's most likely a small fee but i'm willing to pay for that.
[QUOTE=0lenny0;48063222]I see.
Would AT&T unlock my board if i send a request? I don't really have any experience with locked phones but i found some good board's online all being AT&T locked.
I know there's most likely a small fee but i'm willing to pay for that.[/QUOTE]
You can send a request here.
[url]https://www.att.com/deviceunlock/[/url]
[QUOTE=0lenny0;48063222]I see.
Would AT&T unlock my board if i send a request? I don't really have any experience with locked phones but i found some good board's online all being AT&T locked.
I know there's most likely a small fee but i'm willing to pay for that.[/QUOTE]
I have no idea if AT&T will exchange that directly with you, however there's definitely stores and websites that sell those codes to unlock your phone
[QUOTE=halofreak472;48062086]Are there any EE books or online tutorials that cover things from more of a physics perspective? A lot of the stuff I was learning in those starter books didn't make any sense until I took physics classes, but it seems like all of the EM classes offered here past the introductory ones stray really far from EE. Some of the physics books my uni used also tend to skip over bits of detail in order to cover as much information as possible in a short amount of time.
As it is, I hardly understand why voltage looks the way it does when a voltage source is connected in series with two resistors of different values. Basic voltage distribution and ohm's law are always taught in a very empirical way with lots of analogies. I know what happens, I can do the math, and I know how to do more advanced circuit stuff than that, I just don't know where those mathematical models really come from. I've only found a couple of documents that talk about the microscopic reasoning behind it.[/QUOTE]
Microelectronic Circuit Design (4th Ed) by Jaeger & Blalock is a fantastic book for semiconductor physics all the way up through PN junctions, JFETs, BJTs, MOSFETs, etc.
For RF engineering, I recommend Fundamentals of Applied Electromagnetics (6th Ed) by Ulaby, etc. Its quite involved but very detailed and fleshed out. I also recommend using my professor's notes with the book as he made some [URL="http://web.eecs.utk.edu/~ggu1/files/UGHome.html"]great examples/notes[/URL].
I've used all these books before and have saved all my notes/work/project stuff with them, thus I can scan them in for you and/or feel free to PM/post here and we'll help as best as we can.
Microelectronics will get you a better idea of the mathematical models in relation to physics.
I've just spent probably the best part of an hour reading Chryseus' blog.
So with hesitation I parted out a piece of test gear (probes were unobtanium, it was for 240V AC and it was all in german) and salvaged what I could before sending it to the ravine out back. Among other parts pulled out of it....
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_9554.jpg[/IMG]
Oooh. It appears to be a self-contained driver and nixie display assembly. Give it an AC line voltage and display data and the rest is done internally. Hmmmmm. Well I don't want to build another generic clock. What else could I do..........
I know. A GPS!
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Scan0001_1.jpg[/IMG]
[QUOTE=proboardslol;48060867]my 2100 resistors came in the mail!
...
not sure what I can do with them.
I'm still waiting on my 50 tip120 transistors[/QUOTE]
Resistors are things you keep in stock because you'll need them at some point.
I've got like 4-5k assorted THT resistors, and a bunch of random 1206 SMDs, I just ordered some 0603 and I'm probably about to get more.
I really need to buy a shitton of components. I always only order what I need for a project so I never have stuff to tinker with.
My eBay order history is a massacre right now because I only had larger SMD components, and I keep going down in scale.
0805 capacitors, 0603 resistors, 0603 LEDs, a couple of PTCs, some voltage regulators, op amps, aluminium electrolytic caps (47µF 16V 5mm*5mm), solder paste, IPX to RP-SMA cable, RP-SMA antenna, 1206 inductors (10µh), DIP sockets, SMD diodes...
What's the smallest you hand-solder? I really cringe at anything smaller than ssop packages.
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Electrical Engineering V3
