| 摘要 |
<p>A numerical display used for such purposes as programming radio or TV equipment is operated by a single counting chain such that changes to the display are always in the same direction. Switching is reduced by including a second control to permit changes in the opposite direction. Two touch button switches (1, 2) are connected to astable flip flops (3, 4) which are connected to decade counters (5, 6). One circuit (1, 3, 5) provides an increasing count while the other (2, 4, 6) provides a decreasing count. The counters drive decimal logic programme switching circuits (7, 8) whose outputs are decoded (10, 11) to provide binary control signals via a coupling circuit (12) to the display (9).</p> |
