Apparatus for automatically limiting the electron beam current passed through an image display device, such as a television telescope.

摘要

An average beam current limiter for a kinescope responsive to video signals coupled to the kinescope via a signal transmission channel comprises a source of control signals representative of average current drawn by the kinescope. When average beam current exceeds a predetermined threshold level by an amount within a first range of beam current, a corresponding control signal is coupled to the signal transmission channel to vary the D.C. content of the video signal in a direction to limit beam current above the threshold level within the first range. When beam current exceeds the threshold level by a relatively greater amount within a second range of current, a corresponding control signal serves to vary the peak amplitude of the video signal to limit beam current within the second range.