Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
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
Transcoded images for improved trick play
System and method for seamlessly increasing download throughput
Color stable manganese-doped phosphors
Wind turbine
Printed circuit board including electromagnetic bandgap structure
Semiconductor device having a triple gate transistor and method for manufacturing the same
Methods of implanting dopant ions
  Randomly Featured Patents
Semiconductor test apparatus
Therapeutic exercise apparatus
Porous membrane
Diisocyanate derivatives as ashless dispersants and detergents and lubricant compositions containing same
Ion mobility spectrometer utilizing flexible printed circuit board and method for manufacturing thereof
Clock
Adjustable bearing system for paper machine
Method of making microelectronic spring contact elements
Fuel barrier single-layered structure and multi-layered shaped article
Novelty apparatus