Why do X-ray machines for photography use secondary exposure hand switch

X-ray machines for photography are equipped with an exposure hand switch to control exposure. The exposure hand switch has primary, secondary and tertiary styles. The primary exposure hand switch is mainly used for dental X-ray machines, and the secondary exposure hand switch is the most used one, as shown in the figure. It is suitable for various styles of X-ray machines. , The three-level exposure hand switch not only controls the exposure, but also controls the collimator.
Why does the exposure hand switch adopt the second level? The answer is mainly for safety protection. As we all know, X-rays have radiation. Excessive radiation can cause harm to the human body. The exposure hand switch used to control the emission of X-rays plays the role of initial protection for the human body. If there is only one button, it is easy to accidentally cause unnecessary exposure and emit X-rays. Designed as a secondary switch, it is in line with the human body’s operating mechanism. When the first level switch is pressed, the brain’s opponents are not very impressed. It may be an instinctive reaction of the body, but when the second level switch is continuously pressed by force , This instruction must be completed through the brain response. Therefore, the secondary exposure is the instinctive protection of the action of controlling the exposure, reducing the unnecessary generation of X-rays.