Not to get all defensive, but I need to at least throw a little weight this way. First off, I've got a rather good grasp of electronics. Not only do I have an electrolysis machine I built from scratch in my back yard utilizing the power of a 12V battery to generate just over a pulsed 100,000V signal (I guess this would qualify more as a chemistry project, but a bit of electrical to it) but I've also saved and repaired over 60 Macintoshes (desktop and laptops) in my time ranging from numerous problems. I also convert cars from OBD1 to OBD2 (and obd0 to obd1 or 2) which in some cases means making my own harness and adapting sensors to work with the new system (sometimes adapting the signal to fit the new demands).
Now, don't get me wrong. It's been a long time since I've been in electronics (do have a degree in it) so some of the stuff does slip my mind from time to time. And the 170 I wasted is in fact my fault. But only because my numbers were off and I figured the tolerances from the 170 were more than they were. I figured that this 170 would draw much more power than it actually did (hard drive running, backlight to max and charging a battery). What I mean by this is the pack I have is a 12V system now running at 10V. And when your able to pull more current than available, voltage falls (figured 8-8.5 would be more than safe for the 170). But In fact without paying attention it wasn't pulling as much current as I thought and because of this, voltage did not drop and it took the full 10V load (hope that makes sense). And as far as the tongue deal, I've already learned the consequences of that in my younger days because I tried a 9V zap (which is quite enjoyable) and strait 120v (actual here is 112 on an average) which wasn't so pleasant (couldn't taste anything for a day). The occasional 120V zap to the body isn't to bad and can be fun from time to time. But do watch those ignition coils, those deliver a punch, lol. And no, I don't run around zapping myself for fun. It just happens to me more often because I hate having to run and turn off circuit breakers just so I can test some leads. And even if I do get zapped, it's no biggy to me (if the first 100 or so times doesn't do anything, more isn't gonna be any worse). And with cars, it's somewhat unavoidable when testing the ignition system since it has to be running to test. Jake [EMAIL PROTECTED] wrote.......> I don't want to clog this list with a lengthy tutorial on electricity, but I also want to save you from trashing any more Powerbooks. It's my occupation to educate, so here goes one last try (sorry, listers; I can't help it!). You're confused about several fundamental concepts, but let's just look at one. Yes, if you have two power supplies, each, say, 12V, but rated for different maximum currents, the same load connected to each will in fact draw the same current. That's what you probably meant by devices drawing what they will. That's because the current drawn by an element is a function of the voltage you apply across it (as in ohm's law, which applies to resistors), not of the label printed on the side of the power supply indicating its maximum current capability. All absolutely true, and all *absolutely irrelevant* to why you (probably) fried your Powerbook. Unlike this example, you *didn't* apply the rated voltage. You in fact applied a much *bigger* voltage. That's a different situation altogether. And then your Powerbook stopped working after a bit. No surprise there. It's okay not to have a very good grasp of electrical fundamentals (nobody knows everything, and electronics sure is more complicated than a lot of other subjects), but it's less ok that you think you understand much more than you actually do (to the point that you want to debate about it). Please think about why it is that power supplies come in a variety of voltages. It has to do with the fact that electrical devices in fact don't "know" what the "right" current is for them. Do think about that the next time you risk blowing up a perfectly fine Powerbook. :-( And please don't test out your theories by comparing the buzz you get on your tongue with a 9V battery, versus what you get with 120V line power! -- Prof. Thomas H. Lee Center for Integrated Systems, CIS-205 420 Via Palou Mall Stanford University Stanford, CA 94305-4070 http://www-smirc.stanford.edu 650-725-3709 voice, -3383 fax -- PowerBooks is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> PowerBooks list info: <http://lowendmac.com/lists/powerbooks.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/powerbooks%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
