AC vs. DC X-Ray Machines

Q: I have been told that a DC type x-ray machine is better for taking digital x-rays than the AC type machine. What is the difference between a DC machine and an AC machine?

A: The cheapest way to produce x-rays is to use the alternating current that comes from the power company to power the x-ray head. This alternating electric current changes direction in the wires sixty times each second. It also increases and decreases in intensity one hundred and twenty times per second. The effect of using this current is to produce x-rays that turn on and off sixty times each second. Further, the x-rays that are produced each begin too weak to use and grow to proper strength before they decrease again to being too weak. The design of the AC x-ray calls for filters of aluminum to eliminate the x-rays that are too weak to use. This ultimately leaves Sixty pulses of x-ray each some what shorter than one, one hundred and twentieth of a second long each second. The DC x-ray machine uses direct electric current to power the x-ray head. Direct current does not change direction nor does it change intensity. Direct current is a steady supply of power and consequently the x-rays that are produced are smooth and consistent. This smoothness of the DC x-ray machine produces a slightly better effect on the digital sensors than the AC x-ray machine.

Example of an AC Waveform:

waveform_ac

Example of a DC Waveform:

waveform_dc