Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
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
System and method for order placement in an electronic trading environment
Synchronization of communication equipment
Real-time demand prediction in a fast service restaurant environment
Process for the preparation of ethylene homopolymers or copolymers in a high-pressure reactor controlled by a model based predictive controller
Image-processing method and program, and image-processing apparatus
Cap
Method for inhibiting thermal run-away
  Randomly Featured Patents
Low-calorie fat substitute
Static wellhead plug and associated methods of plugging wellheads
Method of making a miniature plug-in fuse with fragile fuse link
Treatment of pervasive developmental disorders with redox-active therapeutics
Torque limiting driver
Collapsible-portable toothbrush holder
Novel asphaltic composition
Process of making fabricated tube construction
Motorized electronic lock
Method and apparatus for determining lane count error in a radio navigational system