| 摘要 |
PURPOSE:To make ICs for 2-hand type and 3-hand type the same by providing control elements for a control circuit controlling the period of the drive pulses driving a converter and leading in the frequency divided outputs of different periods from frequency dividing stages through combination of their opening and closing thereby changing the drive pulse period. CONSTITUTION:Reference signal obtainable from a crystal oscillation circuit 1 is divided down in a frequency dividing circuit 2 and the output 1 Hz signal thereof is fed to an AND 16 and decimal counter 3. The time signal of the 10-second period being the output of the counter 3 is fed to an AND 17 and ternary counter 4. The time signal of the 30-second period being the output of the counter 4 is sent to an AND 18. Control switches 6, 7 are provided for the above and are connected to the NOR circuits 13 thru 15. By the ON-0FF conditions of the same, the outputs of the NOR circuits 13 thru 15 are changed. And the outputs thereof are connected to ANDs 16 thru 18, from which the outputs are inputted via OR circuit 19 to an FF 20, which in turn outputs the pluses for 1-second hand operation, 10-second hand operation and 30-second hand operation as drive pluses from H, I to a converter. |
