Circuit for monitoring the beam current in a colour picture tube

Circuits for controling the beam current in a colour picture tube are generally known since picture tubes have to be protected against overloading by an excessively high beam current. The present invention specifies a circuit which calculates current pictures for the R, G, B beam currents in the colour picture tube, which largely correspond to real beam currents in the colour picture tube, and which contains a comparator/integrator (15) which compares a sum of these current pictures (13) with a beam current information item (ICRT) for the purpose of controlling the R, G, B beam currents and/or the picture sharpness. Gamma correction (12) is carried out in the circuit. The circuit may be of analogue or digital construction and may advantageously be integrated in a video processor IC (2). Applications emerge in particular for television sets or computer monitors.