| 摘要 |
PURPOSE:To eliminate any A/D converter when temperature changes are extracted as changes in the frequency to perform a computation for digital signal processing, by counting a frequency change output with a counter to digitize the temperature changes. CONSTITUTION:A resistance potential divider circuit for measuring temperature is made up of resistances 2 and 4, a thermistor 3, a transistor 5 and a resistance 6 and an output voltage corresponding to temperature detected with the thermistor 3 is obtained with the transistor 5 and the resistance 6. As the output voltage is inputted into the base of a transistor 8, current corresponding to the temperature detected with the thermistor 3 is generated in the collector of the transistor 8. Thus, the charging/discharging period of a capacitor 11 is controlled depending on the value of collector current I0 of the transistor 8 corresponding to the temperature thereby obtaining a collector voltage of a transistor 14, namely, a frequency change output 28.
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