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Everything posted by blek

  1. also have a couple of 115-220V AC plug to USB power adapters to spare. maybe i could rip a few components from those? honestly, i know very, very little about electricity/electronics, and i can't deny it.
  2. basically, i bought this $5 worth of battery holder that is supposed to connect to USB to power some of my devices (basically, a backup source). i already have 4, 3800 mAh AA Ni-MH batteries (or so the label says), so i was like cool. but the thing is the battery holder doesn't really work. so it laid in a tiny box in my room for almost 2 years. now that i'm re-organizing my stuff i found it again. i opened it and no surprise, it doesn't have any regulator of sorts. it just connects the batteries in series. i know, i could just get these: http://www.ebay.com/itm/4-AA-Battery-Holder-Box-Case-1PCS-4-8-5-9V-DC-USB-OUTPUT-Switch-Buckle-/160673519843 nowadays for almost the same price. (albeit it doesn't seem to be able to regulate a constant 5V @ 1A like standard USB does) i have a lot of electronic parts that i've scavenged, so i thought it's a good idea to finally put some of them to use. i figured it needs a stabilized switching regulator to do this, and it would have to be tiny and efficient... any ideas for a schematics, guys?
  3. alright... this is what i'm trying to say... under normal conditions, the circuit is closed for the path to Va, but sometimes, (now this is the unavoidable behavior of the components), a voltage will "SPIKE" towards Vb (well that's not actually what's happening but for a simplified model, we'll think it as such). now, to stop that "spike", we'll have to disconnect the path to Vb temporarily. at the same timeframe of the spike, connection is absolutely opened to Va, therefore, we need a time delay.
  4. alright, would it actually help that there WON'T INITIALLY BE current or voltage difference between the source and drain, as it will be open all that time and the depletion of the gate is simply a way to keep it such open, when there would be a short period in milliseconds that the path from drain to source would be closed.
  5. uhhhh?? no workies?? wahhhh wHAAAA!!! tantantannnnNNNNNN....
  6. ok.... how about..... THIS: [take a'look at attached image!!] tada! more details: oad voltage: ~6V load current: ~500mA ... but it opens it, so i guess breakdown doesn't matter that much gate/trigger: ~6V gate/trigger: ~500mA nyah
  7. waitta... i thought, thought i did, enhancement mode mosfet are normally open and depletion mode are normally closed ???
  8. i'm looking for a component that is normally closed, but when voltage/current is applied to the gate/trigger, it will: 1) open the load (turn it off) 2) keep it open while the current/voltage is applied to the gate at *around the same amount* of trigger current/voltage 3) keep it open for a few milliseconds after the gate/trigger current/voltage drops lower than the holding threshold. 4) after a that immediately closes the load again. i've read that the most reliable way to do this is with a depletion-mode mosfet, but (correct me if i'm wrong), hardly any of them has time delay in the milliseconds range.... so would adding a capacitor and resistor change it??: would it work even if there was no resistor (just the capacitor)
  9. i'm using the pcb designer from orcad 16 suite and by the looks of it, there is no "layer by layer" printing. so can't really "turn-off" the silkscreen and extras all at once.... nope. there is the option changing the visibility option of tolerances, silkcreen, values and those thingamajigs from the screen. but its levels and levels of grouped categories! and each one having checkboxes... dozens and dozens. so my best guess is, it's not the way to "turn off" those extra stuff just for printing. then back on for editing. as i understand, these types of softys output several layers of gerber files each one different. one for tracing, another for solder mask, one silkscreen, etc, etc.. so i thought i'd always have to open the "trace gerber file" with a viewer then print that.
  10. new to de forum guys! neways, so i started teaching myself EDA and specifically designing pcbs. the software i'm using is Orcad PCB Design. so when i'm finished with a project and want to etch it, i'll be transferring it to the pcb using the toner transfer method. but i'm not really sure as to which file to print for that. there's like a .brd file that's directly edited... shows,silkscreen, labels, traces and stuff. but i've learned from reading an ebook that it usually outputs it as a gerber file as a standard. now i'm confused ??? :-[ do i finish it up with the gerber-"jibberish" files, then use a veiwer to print it through, or do i print it directly from *.brd flies?
  11. hi y'all! new to the forum. so i'm looking for a push button that when i press it, it goes on then again goes of. but then has an extra pin that when current is applied, it turns off whatever the previous state was.
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