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
Brushless motor drive apparatus and drive method
Buildable dinnerware
Display apparatus, control method thereof, and program
RF/optical shared aperture for high availability wideband communication RF/FSO links
Resistor and manufacturing method thereof
Device to control force required to depress accelerator pedal
Reaction medium for detecting and/or identifying bacteria of the Legionella genus
  Randomly Featured Patents
Combustion gas desulfurization method
Self-synchronizing hydraulic system
Motor-driven power steering control apparatus
Pencil sharpener
Dinitramide salts and method of making same
Single unit swan fence
Inserts, polycrystalline diamond compact cutting elements, earth-boring bits comprising same, and methods of forming same
Isolation valve used in a single crystal pulling apparatus
Laminated panes and process for the production of same
Vehicle master cylinder