john merryman wrote:
>
> I have a 50ua meter with a resistance 1.085 kilo ohm reading from a
> digital multimeter. I need to get this meter to read 300ma full
> scale, I am having trouble coming up with a correct shunt calculation
> using the formula in the ARRL hanbook, it is not explained in a great
> amount of detail.
---+--Meter---+--- (50uA, 1.085kohm)
| |
+--VVVVV---+ (299.95mA, R ohm)
|<-- E -->|
>From E = IR, you can see 0.00005 x 1085 = 0.29995 x R
-> R = 0.18 [ohm].
But, is the value '1.085 kilo ohm' correct? I can hardly believe it.
73,
Sugi JI3KDH
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