| 摘要 |
<p>Electronic circuit arrangement in a temperature measurement circuit based on a platinum resistor (PT) as a temperature sensing resistor, whereby in addition to the platinum resistor there is provided a reference resistor (R1). The measurement circuit (S) is adapted to apply equally large DC currents (I5, I6) to both resistors having a common return lead (3) from these, and to sense the resulting voltage difference (U) across the resistors. By means of at least one operational amplifier (G) the voltage difference is adapted to cause an output DC current from the measurement circuit (S) being proportional to the voltage difference and thereby constituting a measure of the temperature of the platinum resistor (PT). The measurement circuit (S) comprises means for compensating for non-linearity of the temperature-resistance characteristic of the platinum resistor. Two transistors (T1, T2) are provided, of which the collector output currents (I3, I4) are each adapted to be added to its said respective equally large DC current (I6, I5) being applied to the platinum resistor (PT) and the reference resistor (R1) respectively. The emitter-base voltage of the transistors is adapted to vary depending upon the output DC current from the measurement circuit (S).</p> |
