Multiple Choice __ 29. Which regulates the flow of electrical current to the filament of the x-ray tube? a. high-voltage circuit b. low-voltage circuit c. high-voltage transformer d. low-voltage transformer __ 30. Which is used to increase the voltage in the high- voltage circuit? a. step-up transformer b. step-down transformer c.autotransformer d. step-up circuit

29. **b. low-voltage circuit**<br /><br />The filament circuit, a low-voltage circuit, regulates the electrical current flow to the x-ray tube filament. This controls the temperature of the filament and thus the number of electrons available for x-ray production.<br /><br />30. **a. step-up transformer**<br /><br />The step-up transformer increases the voltage from the incoming line voltage to the kilovoltage required for x-ray production in the high-voltage circuit.<br />