On Sat, 21 Jul 2012 09:47:55 -0700 (PDT), klem kedidelhopper
wrote:

I just pulled a suspect diode out of a dead board. It bears the
numbers SR506. This seems to be a Schottky barrier diode. I haven't
had much experience working with these at all. Normally when checking
conventional diodes I would use my 260 on RX100 ohms. It's very
simple. I read about 500 ohms one way and infinity the other. With
this diode though just after pulling it I read in one direction about
5K ohms with the reading gradually going up.almost like a capacitor
charging. In the other direction I read about 160 ohms. Now after it
has sat on the bench for a few minutes it reads 160 ohms in the one
direction and now reads between 1 and 3 meg depending on which scale
the meter is on.

So then I used a high impedance digital meter. Ther forward reading is
660 ohms and the reverse reading starts out at around 280K and slowly
climbs from there. I didn't leave it long enough to see how high it
would go. I'm not sure what I'm seeing or how to interpret this. If
someone could please shed some light on this I would really appreciate
it. Thanks, Lenny
I always use the diode test scale on my DMM to test these. It should
show a forward voltage of .3 to .4 volts. The reverse characteristics
lead me to suspect it is bad. I'm lucky in that I have a variable
power supply with current meter available to check reverse leakage.
While this diode is rated at 60 volts, if it shows any measurable
leakage at 20 volts I would replace it.

PlainBill