| 摘要 |
PURPOSE:To provide a thermistor thermometer which can obtain a digital temperature output with a simple circuit without a linearizer. CONSTITUTION:A current I is fed from a current source 2 to a thermistor 1. An output of the thermistor 1 is amplified A times to a V(T) by an amplifier 3 and input to a comparator 4. The output is then compared with a discharge voltage (e) of a time constant circuit 5. When the discharge voltage (e) is not larger than the V(T), the comparator 4 generates an output signal which is turned to a predetermined pulse width at a pulse generator 6. As a result, a switch S1 is turned on to charge a voltage Eo. The charging/discharging is repeated afterwards. A temperature is measured by a processing means 7 from a frequency of a pulse signal of the pulse generator 6. |
