JPS5735738A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To control a temperature, by forming a circuit in which such as charging voltage of a capacitor of a time constant circuit repeats charge and discharge between the voltage obtained from radiation energy, which is lower than said voltage, and measuring the period of charge and discharge. CONSTITUTION:Radiation energy of an object to be measured 1 is condensed by a lens 2, is converted to an electric signal by a detector 3, is amplified by alpha times by an amplifier 4, obtains EC, and is inputted to one terminal of a comparator 5. A switch S1 is turned off, a switch S2 is turned on, voltage E0 which has charged a capacitor C in advance is discharged through a resistance R, and when it becomes lower than EC, a pulse generator 7 generates a pulse through the comparator 5. Only during the period of said pulse width, the switch S1 is turned on, the switch S2 is turned off, the capacitor C is charged up to E0, and charge and discharge are repeated. For instance, if said period is made fc, T=kRCfc (k is a constant, R and C are values of the time constant circuit, and T is a temperature of the object to be measured 1). In this way, a temperature is measured easily and with high accuracy by measuring the fc.