Abstract: System and methods may calibrate an AC rms voltage applied to a coronode of a charging device to achieve a predefined operating current at a target value of DC shield voltage. The target value of DC shield voltage may be set to be substantially below an over-voltage condition. System and methods may use a calibration routine that may determine a minimum AC voltage required to achieve the target value of DC shield voltage. Systems and methods may alternatively, or additionally, sense current and adjust the applied voltage to obtain a target current.

Abstract: An electrophotographic document production device having a transformerless high voltage power supply located distal to its load and a transformer at the point of load.

Abstract: Techniques for correcting for internal resistance losses in the secondary windings of a transformer to reduce errors in output voltage from a high voltage power supply.

Abstract: A lamp fixture for mounting a high intensity discharge (HID) lamp. The lamp fixture integrates components needed to operate the HID lamp, including a lamp socket and a ballast, into a compact assembly covered by an enclosure. The fixture facilitates dissipation of heat from the lamp and ballast through a base mounting so that thermal insulation of the ballast transformed is not required, thereby reducing the weight of the device. The fixture may further include a diffuser mounted to the enclosure to distribute light from the HID lamp in a uniform manner. The fixture is particularly useful for mounting HID lamps within illuminated signs.