Click here to return to the home page.

The photograph shows the regulator, a "T" shaped tube attached to the bulb of the X-ray tube. Inside the regulator is a bundle of asbestos fibers, wrapped around the asbestos is an iron wire, connected to the terminals shown. To regulate the tube a 12 v battery is connected to the terminals, and the asbestos heated up. This releases gas entrapped in the fibers, which lowers the operating voltage.
This process would need to be repeated about once per week in a busy department, if the working kV was to be kept within reasonable limits.