| 摘要 |
PURPOSE:To automatically set the timer of an air conditioner, by a method wherein the alternating wave form of a commercial power source is converted to a rectangular wave form and the pulse number counting value of the frequency thereof is compared to an upper and a lower limit set values to automatically judge the frequency of the commercial power source. CONSTITUTION:The alternating wave form of a commercial power source is converted to a rectangular wave form by the full-wave rectification circuit 61 and the Schmidt circuit 62 of a wave form conversion circuit 6. During the rising or the falling of this wave form, the counter circuit 71 of a pulse counter 7 counts a clock pulse and the counted value is applied to a first and a second comparator 91, 92 to which an upper and a lower limit values are set. In this case, when the counted value of the circuit 7 is within a range of the upper and the lower limit values, the output of an AND gate 93 having reversion input applied to one side thereof comes to a high level and, when the counted value is the upper limit value or more, the output of an AND gate 94 having a high level inputted to one side thereof reaches a high level to generate high level judging output from a shift register and the AND gates 95, 97 or AND gates 96, 98. By this method, frequencies of 60Hz and 50Hz are automatically judged to automatically set the timer of an air conditioner. |
