Circuit arrangement for providing a saw-tooth current in a coil

A circuit arrangement for providing a periodic saw-tooth current in a coil, such as a kinescope deflector coil (11a, 11b) comprising:

• a one-way conducting device (8) having one end immediately coupled to a pole (1) of a voltage source (1, 2) and the other end coupled to the coil;
• a thyristor (4) having one terminal connected to the other pole (2) of said voltage source and having a control electrode (5) which may be coupled to an extraneous periodic pilot-pulse source which makes said thyristor conductive at the end of the trace interval of the saw-tooth cycle;
• an autotransformer (3) having one end connected to said one pole (1) of the said voltage source (1.2), an intermediate tap (3a) connected to the other terminal of said thyristor (4), and the other end connected to a rectifier (22) to provide a high D.C. voltage output for the acceleration electrode of the kinescope;
• a capacitor (10) having one end connected to said intermediate tap (3a) of said autotransformer (3) and to said other terminal of said thyristor, and the other end connected to said other pole (2) of said voltage source (1.2);
• a transformer (13) having a primary winding, connecting said intermediate tap (3a) of said autotransformer (3) to said other terminal of said thyristor (4), and a secondary winding connecting said other end of said one-way conductive device (8) to said other pole (2) of said voltage source (1.2);
• wherein said transformer is sized to have a primary inductance with the secondary short-circuited which, together with said capacitor (10) forms a time constant sufficiently great to keep the thyristor conductive throughout all the retrace interval and for the first part of the trace interval of the saw-tooth cycle.