| 摘要 |
<p>PURPOSE:To prevent reduction of dehumidification capacity resulting from frost sticking on a heat sink by providing a controlling circuit by which the polarity of supply voltage for being impressed to a thermoelectric transducer is contrarotated for a constant time in response to the output of a temp. sensor fitted to the heat sink. CONSTITUTION:When turning on a power switch, electricity is supplied to a controlling circuit 14 and a fan 7 is rotated. When the temp. of a fin 4b fitted to a heat sink 4 is higher than the freezing temp. of water of dew condensation, supply voltage for being impressed to a thermoelectric transducer 3 is positive polarity and the temp. of a radiator 2 is raised and the temp. of the heat sink is lowered to perform dehumidification. On the other hand, when the temp. of the fin 4b reaches freezing temp. or below, resistance value of a sensor 13 become higher and the supply voltage shows reverse polarity and both a high-temp. face and a low-temp. face of the thermoelectric transducer 3 are contrarotated. After lapse of a fixed time, the supply voltage is returned to positive polarity and the temp. of the heat sink 4 lowers again to perform dehumidification.</p> |
