Simpson Meter

[W6CUX]

First you need the basic meter sensitivity and the meter resistance. Then it
becomes an ohms-law problem. Let's say that the basic meter is a 0-1mA with
a resistance of 50 ohms. Find the voltage to deflect the meter full scale.
1mA x 50ohm = 50 mV.Then shunt resistance = 50mV / 749 mA (use 750 mA) =
1/15ohm = .067. Pretty small.

A better way would be to place a resistor in series with the meter -- say
175 ohms. Then 1mA x (50+175) = 225 mv. The shunt is 225/750 = 0.3 ohm.
(still small.)

73, Stu W6CUX

----- Original Message -----
From: "w0akg1" <w0akg1 at EARTHLINK.NET>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Monday, November 29, 2004 12:31 PM
Subject: Simpson Meter


I'm a little Rusty, have a Simpson 0-750 MA meter. How can I tell if it
needs a shunt and how do I figure the shunt? Thanks Guys. Model number is
127.
Martin Tippin WØAKG
31 Circle Dr.
Windsor, Mo 65360

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