Diode help... HELP! - test-drb@ccmp.vtda.org

22 Feb 2000

On February 22, Bill Sudbrink wrote:
...
  Once again demonstrating my vast quantities of
ignorance...
 I need a diode which completely blocks current in one direction
 and presents as little resistance in the other direction
 as possible.  I bought a fist full of little glass ones at
 Radio Shack for 50 cents.  On my Ohm meter, they show no
 conductance in one direction and 1400KOhm the other way.
 What do I need to get?  RS (which is the only resource I
 have available, I need them like _NOW_) has many different
 kinds of diodes, ranging up to two dollars per pair. 
  Hmm...keep in mind that all semiconductor diodes exhibit a forward
voltage drop...0.3v for germanium and 0.7v for silicon diodes.  If
your multimeter isn't using more than that forward voltage drop to
measure that "conducting-mode" resistance, you won't get anywhere with
that measurement method.

      -Dave McGuire