A self-oscillating vertical circuit using a dual-control pentode tube

From the early days of commercial television to the present time, only a limited variety of vertical-scanning circuits have been introduced. The trend has been to use dual triode circuits, often in intricate and critical arrangements that required high-precision components. As a result, vertical circuits have been relatively difficult to maintain, and the over-all costs of these circuits have been high. These conditions still persist, although to a much lesser extent, in the modified multivibrator type of vertical circuit that is most widely used today. This paper describes a self-oscillating vertical circuit that is simpler and more reliable than the present multivibrator type and that has substantially improved performance characteristics. The increased simplicity and reliability will greatly ease the maintenance problem and substantially reduce circuit costs.