| 摘要 |
PURPOSE:To decrease the number of input keys and to improve the operability, by varying the resistance value to a level set previously when two keys are operated at one time. CONSTITUTION:A presetting circuit 19 and an LOAD terminal 20 are provided to an up-down counter 9. In addition, an OR gate 21 is added to the counter 9. Then an UP key switch 13 and a DOWN key switch 14 are closed at one time. Thus the output of an OR gate 21 is instanganeously set at L level and then supplied to the terminal 20. As a result, the value preset at the circuit 19 is immediately delivered to an output terminal 10 of the counter 9. Then the prescribed one of the electronic switches 4 is turned on, and the output signal of a prescribed level which is set previously is obtained at a signal output terminal 5. In such a way, the number of input keys is decreased and the operability is improved. |
