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
Etching composition
Access control method, information display device using the same, and information display system
Communication apparatus and communication system
Dynamic lookup service in a distributed system
Method for cutting C--Mn steel with a fiber laser
Rapid glycopeptide optimization via neoglycosylation
Ottoman
  Randomly Featured Patents
Compositions containing green tea catechins and one or more polyvalent mineral cations
Apparatus for forming bells on plastic tubes
System and detector for measuring by means of sound the liter weight of the material in satellite coolers for rotative ovens
Software program for managing and protecting data written to a hybrid solid-state disk drive
Brushless motor with an improved connector terminal
Electronic music synthesizer
Process for the preparation of nitrophenyl hydroxy substituted acetylenes
Mirror assembly with single heating element for multiple surfaces
Device for impact sensing
Video enhancement and display power management