Resources Contact Us Home
Noncontact temperature measuring device

Image Number 2 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
UV exposure method for reducing residue in de-taping process
Variable delay line for delay locked loop
Monitoring cloud-runtime operations
High-performance AHCI interface
Use of Lactobacillus for liver protection
Biaxially oriented hydrolysis-stable polyester film comprising epoxidized fatty acid derivatives and a chain extender, and process for production thereof and use thereof
CMOS image sensor
  Randomly Featured Patents
Hydrogen circulation for moving bed catalyst transfer systems
Novelty T-shirt
Procedure for the analysis of biological substances in a conductive liquid medium
Device for gripping a blow-moulding container preform
Multiple image high dynamic range imaging from a single sensor array
Abrasive product and method of making the same
Optically active compound, liquid crystal composition and liquid crystal device comprising same
Reclamation of components of wellbore cuttings material
Organic electroluminescent device having high efficient luminance
Contact and connector for terminating a pair of individually insulated wires