| 摘要 |
PURPOSE:To obtain a frequency oscillating output that is exactly proportional to temperature, by applying a serial circuit that is composed of both a resistor whose resistance value is almost invariable with temperature, and a thermistor whose resistance value is variable with temperature, as a variable resistor of frequency. CONSTITUTION:A variable resistor 5 of frequency is constituted by a serial circuit composed of both a resistor 8 whose resistance value is almost invariable with temperature, and a thermistor 9 whose resistance value is variable with temperature. In this case, when the resistance values of the resistor 8 and the thermistor 9 are denated by R3 and RT1, respectively, the composite resistance value R of them is expressed as R=R3+RT1, and the resistance value RT1 of the thermistor 9 is expressed by an equation I , where R01 is the resistance value at an ambient temperature of To deg.K, To is generally set to 298 deg.K (25 deg.C) as a standard, and B1 is the thermistor constant. The reciprocal Y of the composite resistance value R is expressed by an equation II. Then the resistance values R3 and R01, and the constant B1 are selected respectively so that the reciprocal Y is linear to the change in temperature. |
