ante Posted July 10, 2004 Report Share Posted July 10, 2004 Audioguru,Sorry, I was starring at the wrong transistor on my drawing!I need some sleep obviosly!Ante ::) Quote Link to comment Share on other sites More sharing options...
audioguru Posted July 11, 2004 Report Share Posted July 11, 2004 OOOps,Ante,I wish that I could just copy and paste a piece of a FDF file. This schematic is like your last one, and is from Fairchild, who got it from ON Semi., who got it from Motorola.I think that your 100 ohms doesn't allow enough current for the regulator, so I used 10 ohms.Also, I think that your little 2N2905 will be smokin'. ;D Quote Link to comment Share on other sites More sharing options...
GPG Posted July 11, 2004 Report Share Posted July 11, 2004 Q2 will supply current to the regulator (until it smokes) Quote Link to comment Share on other sites More sharing options...
audioguru Posted July 11, 2004 Report Share Posted July 11, 2004 Hi GPG,The regulator won't smoke because it has built-in current-limiting and thermal-shutdown.Q2 won't get "too" hot since it never has much voltage across it.Q1 will need a big heatsink since it has nearly the full source voltage across it and plenty of current through it. Quote Link to comment Share on other sites More sharing options...
ante Posted July 11, 2004 Report Share Posted July 11, 2004 Audioguru,You can use the Prt Sc (print screen) to copy from any document and just paste it in paint, cut it to size and you are done! Try it! The circuits is almost the same, I like to have the protection diode in there also. The value of R1 is not very important but if you use higher value there is no need to cool the regulator. It will then go faster into thermal protection in case of a short circuit. I have encountered cases where regulators have been Quote Link to comment Share on other sites More sharing options...
audioguru Posted July 11, 2004 Report Share Posted July 11, 2004 Thanks, Ante,If I do a Print Scrn (shifted, so I don't get SysRq), then I don't know where it is stored (Windows Temp. is empty). Then I open paint, and the only action that I have is "Edit - Paste from". Since I don't know where it is stored, then I also don't know where to paste it from.I don't think that my Print Scrn button works.Now the booster again:1) Without a load, if the regulator's idle current flowing through your 100 ohm resistor turns-on the boost transistor (it is close), then the circuit's output voltage will rise very high, and even your protection diode won't prevent it. Then if the voltage is high enough to cause avalanche-breakdown of the resulting reverse-biased emitter-base junction of the regulator's pass transistor, the boost transistor may pump lots of current into that avalanching junction and maybe destroy it. 2) Do you know if a regulator that has gone into thermal-shutdown, will start working again after it has cooled? Quote Link to comment Share on other sites More sharing options...
ante Posted July 11, 2004 Report Share Posted July 11, 2004 Audioguru,I don Quote Link to comment Share on other sites More sharing options...
GPG Posted July 12, 2004 Report Share Posted July 12, 2004 Q2 will supply current to the regulator This can reach 2.5A Quote Link to comment Share on other sites More sharing options...
MP Posted July 13, 2004 Report Share Posted July 13, 2004 ante, I do not think screen dump is supported in Win98 1st edition.MP Quote Link to comment Share on other sites More sharing options...
ante Posted July 13, 2004 Report Share Posted July 13, 2004 MP,I am not sure but in an old laptop I have with W98se it works. I don Quote Link to comment Share on other sites More sharing options...
MP Posted July 13, 2004 Report Share Posted July 13, 2004 Yes, I also have a laptop with Win 98 SE. It works in mine also. There was a lot of difference between win 98 1st and 2nd editions. I had 1st edition at some point but I cannot remember what I did with it. Probably threw it away. The second edition is much larger. I think of the second edition as the real thing and the 1st edition as the introductory sample of the operating system.MP Quote Link to comment Share on other sites More sharing options...
audioguru Posted July 14, 2004 Report Share Posted July 14, 2004 Yeah,My Print Screen button doesn't do anything in Win98 1st Ed.My whole computer is just an introductory sample of the real thing! Quote Link to comment Share on other sites More sharing options...
ante Posted July 14, 2004 Report Share Posted July 14, 2004 MP, AudioguruI don Quote Link to comment Share on other sites More sharing options...
audioguru Posted July 14, 2004 Report Share Posted July 14, 2004 Ante, MP,Thanks guys, ALT + Print-Screen works fine and I can paste it into Paint.Upgrade?Not yet. The computer is only a tool, and you guys help me a lot with it, thanks again.You should see my trusty (not rusty) single-channel, vacuum-tube (except my CMOS timebase, sync and transistorized horiz. amp) AC-coupled (350V vert. amp) 'scope! Quote Link to comment Share on other sites More sharing options...
ante Posted July 14, 2004 Report Share Posted July 14, 2004 Audioguru,Congratulations, you found a key combination that worked! Well then there is no reason to upgrade yet! ;D Tube scope? I hade one of those 20 years ago and it was old then! It was a Trio Advance scope it weighed about 25 kilos or so.Ante ::) Quote Link to comment Share on other sites More sharing options...
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