Need Help!! Current - Weston-type ammeter

[AnthonyR23]

Hi, I am working on a unit for my electro- course... I have the answer but am having trouble working out this question.... if someone could help that would be awesome!!

Question:
If a Weston-type ammeter with a coil resistance of 12.6 ohms has a shunt resistor of 1.92 ohms, which is dissipating 930 mW of power, how much current is going through the meter coil?

Answer:
106.1 mA

I am trying to work this out... but am having a lot of trouble...

Formula Shunt Current / Meter Current = Meter Resistance / Shunt Resistance

Thanks!! This is the one question that is holding me up... before my exam...

 

[Tesla23]

Hi, I am working on a unit for my electro- course... I have the answer but am having trouble working out this question.... if someone could help that would be awesome!!

Question:
If a Weston-type ammeter with a coil resistance of 12.6 ohms has a shunt resistor of 1.92 ohms, which is dissipating 930 mW of power, how much current is going through the meter coil?

Answer:
106.1 mA

I am trying to work this out... but am having a lot of trouble...

Formula Shunt Current / Meter Current = Meter Resistance / Shunt Resistance

Thanks!! This is the one question that is holding me up... before my exam...

Ignore the formulas, think about what is happening. The 1.92ohm shunt is dissipating 930mW so the voltage across it is sqrt(1.92*.93) = 1.3363V, so the current through the 12.6ohm meter is 1.3363/12.6 = 106.1mA.

 

[AnthonyR23]

Thanks!!!!!!!!!!!!!!!!!!!!!