[Elecraft] KA100: "diode check scale"?

[Don Brown]

Hi

DVM's measure resistance by applying a constant current to the circuit an=
d measuring the voltage drop across the leads. On some ranges the applied=
 voltage is less than the turn on voltage for a diode so these ranges can=
not be used to check a diode. The ranges that will turn on a diode are us=
ually marked on the meter with a diode on the range switch (usually 1K ra=
nge) Even though you are on ohms the reading will indicate the voltage dr=
op of a diode when the leads are connected so the diode is foward biased.=
 Some meters will have a special diode checking range to do this if not t=
ry measuring a diode out of circuit on each ohm range. Look for a range t=
hat measures about .600 with the diode connected forward and over range r=
eversed

Don Brown
KD5NDB

----- Original Message -----
From: Tim and Nancy Logan
Sent: Saturday, August 03, 2002 4:26 PM
To: Elecraft
Subject: [Elecraft] KA100: "diode check scale"?

Hi Folks - I don't understand the expression "diode check scale" on page
14 of the amp manual. If I use the voltage scale none of the readings
seem to be in the ranges required. However, I did make the following
resistance measurements:

D1 - D8 .6M ohm (red lead on anode) and infinite (OL)  (black lead on
anode)
D9 - .4k ohm                            316k ohms
D10 - 4.7M ohms                         infinite (OL)
D11 - .67M ohms                         infinite (OL)
D12 - .57M ohms                         infinite (OL)
D13 - 4.2M ohms                         infinite
D14 - .57M ohms                         infinite
D16 & D17  - 51k ohms                   infinite

If I assume that OL means no resistance, this would suggest the diodes
are all OK (except for D9?). Can someone explain how to use the DMM to
check
the voltage? Will my resistance checks suffice? =20

Regards, Tim Logan NZ7C
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