| 摘要 |
<p>1,229,333. Automatic temperature control systems. SIEMENS-ELECTROGERATE G. m. b. H. May 24, 1968, [May 26, 1967], No.25062/68, Heading G3R. A Peltier element 12 for heating or cooling is controlled by a NTC resistor 10 through threshold device 7, such as a Schmitt trigger circuit, and a transistor 8, which in one embodiment increases the frequency of an oscillator including transistors 20, 21, hence reducing the current to element 12 to an ineffective low value. In another embodiment Fig. 1 (not shown) transister 8 controls the firing angle of a pair of thyristors (2,3) in an on/off manner. For both heating and cooling two resistors 10 are employed connectible alternatively, either through diodes or through change over relay contacts. In a further arrangement is arranged for forced ventilation of the Fig. 3 and 4 (not shown) a fan driven by a motor 23 Peltier elements which are fed from a transistor oscillator.</p> |
