An x-ray machine is a complex device used in a variety of circumstances around the world. With the ability to penetrate hard objects, they are used for purposes such as airport security checkpoints to see into bags, or in the medical community to look for broken bones or problems within the body. Regardless of which type of x-ray you are discussing, there are a number of components that are vital to the inner workings of an x-ray machine.
X-ray tubes are more commonly referred to as vacuum tubes. They are integral parts of the x-ray machine, and work by ionizing radiation with wavelengths shorter than ultraviolet light. A cathode within the machine emits electrons into the vacuum tube, at which point an anode collects the electrodes and establishes an electrical current through the tube. A high voltage is used to accelerate the electrons, and the current flow is pulsed until the required amount of x-ray exposure has occurred. The beams of energy from the tube are focused onto a visible substance, which is where you view the final result.
A high voltage power source is required to operate an x-ray machine, usually between 30 and 150 kilovolts depending on the type of x-ray being taken. The voltage is used to accelerate the electrons within the vacuum tube, and is usually pulsed from 1 microsecond to 1 full second. The high voltage power source of an x-ray machine controls the penetration of the x-ray itself, and thus the overall contrast of the image, with the voltage of the current and exposure time affecting the dose and darkness of the image.
The control unit of the x-ray machine is necessary to manage the current, voltage, and time of exposure. Radiation intensity can change dramatically depending on whether you are using the machine to render x-ray stills of body parts or using it as a security monitor, for example. In addition there is a voltage control with a display, allowing you to make adjustments in the anode itself to change the type of radiation energy being released. The control unit also has a timer to control the pulses and duration of the exposure, shutting the current off when the radiation exposure has been completed.