Horizontal convergence circuit

Abstract

Abstract A horizontal convergence circuit having a pair of convergence coils coupled in series with the secondary of a transformer. Means are provided to apply a voltage pulse waveform at the horizontal repetition rate to the transformer and thereby develop a sawtooth current in the respective convergence coils. Means are also provided to apply a sawtooth voltage across the coil which when integrated in the coil develops parabolic currents. The combination of the parabolic currents and sawtooth currents provides the necessary magnetic field to converge the associated electron beams in a cathode ray tube. The secondary winding of the transformer which is used to supply the pulse voltage to the convergence coils has readily releasably connectors for coupling opposite leads of the secondary winding to the respective convergence coils. Pins are provided on the leads of the coils and these pins are received within the connectors. By reversing the points of coupling of the pins in the respective connectors, the direction of sawtooth current in the two convergence coils can be reversed. In this way, convergence is made possible in circumstances where the normal sawtooth amplitude adjustment devices could not accomplish convergence. The secondary winding of the transformer has a center tap which is coupled through a potentiometer to circuit ground. The center tap also has a connector which may receive either one of the pins associated with the leads of the respective convergence coils. In this way, the sawtooth level in either one of the coils may be substantially reduced to zero without affecting the level of sawtooth current in the other coil. As in the case of reversing the direction of current, this greatly extends the range of adjustment for the sawtooth current.

Inventors

• 👤 Lawrence R Poel

Bibliographic Details