| 摘要 |
PURPOSE:To suppress the abrupt electric power change of a heater by a method wherein a means for holding for a predetermined time is given to the receiving side of a device a device detecting the change of the form of a space within the 'kotatsu' by means of ultrasonic wave. CONSTITUTION:A means for transmitting ultrasonic wave 5, a means for receiving the wave 6 and the heater 3 are provided in the space 2 within the body 1 of the electric 'kotatsu'. The receiving means 6 consists of an ultrasonic oscillator for receiving 9, an amplifier 10, a detector 11, a differentiator 12, a comparator 13 and a standard value setting circuit 14 and the output of the means 6 is inputted in a controller 7. The controller 7 has the holding function 1 comprising a counter means and a memory means, rendering in sending a controlling output to the heater 3 after the elapse of predetermined time (for example, after 10-30sec) since the receipt of signal from the receiving means 6. |
