(A or amp) The SI base unit of electric current.
Definition: Two parallel conductors, infinitely long and having negligible cross section should be placed 1 meter apart in a perfect vacuum. One ampere is the current that creates between them a force of 0.2 µN (micronewton) per meter of length.
One ampere represents a current flow of 1 coulomb of charge per second.
One ampere of current results from a potential distribution of 1 volt per ohm of resistance, or from a power production rate of 1 watt per volt of potential.
The unit is known informally as the amp, but A is its official symbol and is named for the French physicist André-Marie Ampère.
See also System International.

(mA): 10^-3 ampere. In radiography, the current flow from the cathode to the anode in the x-ray tube is measured in milliampere. This current regulates the radiation intensity emitted by the x-ray tube.

See X-Ray Tube.

(mA min) The product of the x-ray tube operating current and the exposure time in minutes.

See Milliampere and X-Ray Tube.

(mA s) The product of the x-ray tube operating current and the exposure time in minutes.
See Milliampere and X-Ray Tube.

Coulomb is the SI unit of electric charge. One coulomb is the amount of charge accumulated in one second by a current of one ampere.
The charge of a proton is 1.6 x 10^-19 coulombs. The charge of an electron is - 1.6 x 10^-19 coulombs. An atomic particle has a charge which is an integral multiple of 1.6 x 10^-19 coulombs.