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Transistors

Started by Hilikus, November 09, 2004, 06:49:53 PM

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Hilikus

OK I hope I'm not butchering the terms here but could anyone direct me to info on how to set the trim pots (acting as collectors?) for transistors on a stompbox project? (It's the "eighteen" box @ runoffgroove.com)
     I'm new and am trying to learn how to use a multimeter but don't know what leads I'm supposed to be taking readings from.

Sorry for the dumb questions but thanks for any help!

John

petemoore

Second answer...black to ground [common] and red to whatever you want to measure the voltage potential of. In DC circuits like StompBoxes,
you'll use DC 20V range setting on the DMM...whoops I'm talking about my DMM...anyway whatevers getting readings that 'cover' 9V or more...if the Voltage is higher the DMM wont read till you set it for a higher range.
  First answer...at the top of these pages are links to Debugging, FAQ, and all kind of info to the reading browser...
  Anyway besides everything else ^, including Jfet pinouts, you want the drain set at 4.5v of 9v supply or 1/2 voltage...there abouts [set to ear?...etc.], I think. Could be theres' an emitter follower in there, in which case the Jfet drain would be looking for 9v. If the schematic says 'it' connects to ground, 'it' should read 0v or continuity to ground.
  if it says 9v then 9v potentail should be seen from ground. If there's some kind of divider, then the voltage read from ground has to be between 0v and 9v...two equal value resistors, seriesed between - and +, gets you 1/2v.
 Check for shorts between - and +, don't connect a battery if you're getting continuity.
 Check for continuity to ground at all ground points.
Convention creates following, following creates convention.