You can't directly measure the "value" of amplitude in an electric current, because amplitude is not a singular value but a characteristic of the current.

Here's what you need to understand:

* Amplitude: The maximum value reached by the current in a cycle. It's a measure of how strong the current is at its peak.

* Direct Current (DC): A constant flow of electrons in one direction. Its amplitude is simply the constant value of the current.

* Alternating Current (AC): A current that periodically changes direction. Its amplitude is the maximum value it reaches in either direction.

Here's how you can measure the amplitude of an electric current:

1. For DC: Use a multimeter set to the appropriate current range (mA or A). The reading on the multimeter will directly show the amplitude of the DC current.

2. For AC:

* Using a Multimeter: Most multimeters have a setting for measuring AC current (usually labeled "ACmA" or "ACA"). This will measure the root-mean-square (RMS) value of the current. The RMS value is not the same as the amplitude, but it's useful for calculating the power dissipated in a circuit.

* Using an Oscilloscope: An oscilloscope can directly display the waveform of the AC current, showing its amplitude (peak-to-peak value) and frequency. You can then measure the peak amplitude directly from the oscilloscope display.

In summary:

* The amplitude is not a value itself, but a characteristic of the current that tells you how strong it is.

* You can measure the amplitude of DC current directly using a multimeter.

* For AC current, you can use a multimeter to measure the RMS value, or an oscilloscope to visualize the waveform and measure the peak amplitude.