Hi Sverre,
You are absolutly right! I totally forgot about the current sensor in
KPA100 - i havent looked at the schematics for awhile. I think i can even
use the I SENSE signal which already has swing 0-5V. Using an op-amp buffer
with high impedance input should not affect the signal and than it is a
matter of an adjustable voltage divider to get it down to 0-1V (QM-130V).
Peak-holding feature might be a good ideas since QM-130V samples 10 times
per sec and its not difficult to add. QM-130V has 9 segments so choosing
swing 0 to 27A will result in an exact 3A per unit display - should be
accurate enough to detect current anomalies at high power levels..
Small PCB attached to the back of the front panel should do the trick. Now I
have to find time to build it :-)
73s
----- Original Message -----
From: "Sverre Holm" <[EMAIL PROTECTED]>
To: "'Andrey Stoev'" <[EMAIL PROTECTED]>
Cc: <elecraft@mailman.qth.net>
Sent: Sunday, May 01, 2005 5:25 AM
Subject: RE: [Elecraft] LCD Voltmeter mod for KPA100/KAT100 in EC2
-----Original Message-----
The URL for the meters :
http://www.marteltesttools.com/products.php?cat=113&action=detail&id=69
QM-100V
QM-110T
QM-130M or QM-140V might work for an amp-meter. Proper current sensing
resistor (shunt) will be needed and some other components.
---------------
Nice idea with the KPA1100 metering. The KPA100 already has a current
sensing resistor in the 12V line: R7 0.005 ohms. At 20A it gives 100 mV,
so
maybe it can be used?
73
Sverre
LA3ZA
http://www.qsl.net/la3za/
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