| 摘要 |
<p>A temperature control apparatus including an AC bridge formed by four legs connected together to form first, second, third and fourth nodes. One of the legs is in the form of a temperature responsive resistor and a second leg includes a heating operator for operating a heating system. A cooling operator is provided for selectively operating a cooling system. A gate-controlled conduction device is incorporated in the bridge for controlling current to the operators and includes an anode and cathode. Respective first, second and third lead means connects the cathode with the first node, the gate with the second node, the anode with the third node and fourth lead means connects the cooling operator between such anode and the fourth node. Current-directing means is provided for selectively directing current through the third or fourth leads whereby unbalance of the bridge in response to cooling of the temperature responsive resistor will trigger the conduction device and initiate current flow in the heating operator and unbalance of the bridge in response to heating of such temperature responsive resistor will also trigger the conduction device and initiate current flow through the cooling operator without substantially changing the current flow in the temperature responsive resistor to thereby avoid any change in self-heating thereof.</p> |
