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
Portion of display panel or screen with an icon
Solar cell using polymer-dispersed liquid crystals
Method for dynamic multi-level pricing for wireless communications according to quality of service
Wafer recycling method
Ignition device in particular for an internal combustion engine, and method for manufacturing same
Firewall-tolerant voice-over-internet-protocol (VoIP) emulating SSL or HTTP sessions embedding voice data in cookies
Intrinsic absorber layer for photovoltaic cells
  Randomly Featured Patents
Compact driving unit for an automatic banknote receiving and storing device
Image processing device and method for pixel data conversion
Plasma treatment method in electronic device manufacture
Antiinflammatory 2-substituted-thio-4,5-dihydro-4,5-diaryl-1H-imidazoles
Vehicle bumper beam
Digital data transmission system with time division/packet transformation function
Method of producing an optical connecting component, and optical connecting component
Printing apparatus and control method
Paint sprayer
Structure for sensing refrigerant flow rate in a compressor