基本信息
摘要：1,008,473. Measuring temperature electrically. May 29, 1964 [May 30,1963], No. 21747/63, Heading G1N. The junction temperature of a semi-conductor device 10 is measured by adding two signals V 1 and V 2 , one of which, V 1 , represents the temperature of an external part of the device 10 as measured by a thermistor 12 mounted on the same heat sink 11 as the device, and the other of which, V 2 , is derived in a circuit, 9, from the output of a current transformer 16 whose primary 17 carries the current which flows through the junction. The signal V 2 is said to be proportional to the temperature difference between the outer parts of the device and its junction. The circuit 9, which represents an electrical analogue of the thermal circuit of the device, contains capacitors 21 to effectively short circuit any transients in the junction current, which would not affect the junction temperature because of the thermal inertia of the device and therefore are required not to produce any effect upon the signal V2. The voltage V3 may be compared with a reference voltage and used to operate a protection relay if it exceeds a predetermined value.
摘要附图：
