Ammeters & Frequency: Understanding the Relationship

[The_Lobster]

Homework Statement

Do you think a meter will handle an a.c. current of any frequency?

Homework Equations

The Attempt at a Solution

Since we can illustrate an ammeter as a moving coil with a resistor in parallel, and since all elements in a circuit will exhibit inductive and capacitive behavior when the frequency is any other than 0 Hz, the impedance across the parallel resistor will increase with increasing frequency as the inductive reactance increases ($$X_L = \omega L$$) (while the capacitive reactance nears 0), so more and more current will bypass the shunt resistor and go straight through the moving coil of the ammeter and this could clip it (?).

Though, since the moving coil also has *some* resistance, this will also have increasing impedance with increasing frequency, so the above might not hold?

 

[vk6kro]

The moving coil has a lot more resistance than the shunt resistor.

If you regard the resistance of the coil as being in series with the coil and assume the resistances do not change, and assume the total current does not change...then what happens to the impedance of the coil at higher frequencies?

Remembering current division, how does the current split up at higher frequencies?

What effect will this have on the meter reading?

Is there a very simple way to avoid this problem?