Resources Contact Us Home
Noncontact temperature measuring device

Image Number 6 for United States Patent #4456390.

A portable, battery operated noncontact temperature measuring device including a lens for collecting infrared radiation and a thermopile for producing a signal indicative of the intensity thereof. The thermopile signal is amplified, linearized and summed with an ambient temperature signal derived from a temperature responsive element, e.g. a diode chip mounted immediately adjacent a cold junction of the thermopile. The resulting composite temperature signal is then processed and displayed. The ambient temperature signal is also utilized to control the impedance of a dual field effect transistor, which in turn controls the gain of the amplifier. Thus, temperature induced variations in the responsivity of the thermopile are compensated by corresponding changes in the gain of the amplifier. An adjustable high impedance bias circuit provides bias current to the input of the amplifier, insuring that the signal at the output of the amplifier will not be affected by temperature induced changes in the internal resistance of the thermopile. A switching circuit alternately connects the output of the thermopile and a resistor having a resistance approximately equal to the internal resistance of the thermopile to the input of the amplifier. When the resistor is so connected, an automatic zeroing circuit reduces the amplifier output to approximately zero, thereby essentially eliminating amplifier drift.

  Recently Added Patents
Light-source control device, light-source control method, image reading device, and image forming apparatus
Image forming apparatus and image forming method
Modular connector for touch sensitive device
Intralevel conductive light shield
Switchgear operating apparatus and three-phase switchgear
Apparatus for providing location information of hand-held device and method thereof
Method for preventing wheat from mycotoxin contamination
  Randomly Featured Patents
Methods and apparatus for measuring morphology of a conductive film on a substrate
Turbine surge detection system
Internal combustion engine having a rotating piston assembly
Process for forming re-entrant geometry for gate electrode of integrated circuit structure
User voice mixing device, virtual space sharing system, computer control method, and information storage medium
N-phenyltetrahydrophthalamic acid derivatives, methods of producing same, and herbicides containing same as effective components
Bird bath with reservoir
Production of UHMWPE sheet materials
Device for connecting reinforced concrete sections
Convertible railway-highway vehicle