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
Composite materials comprising aggregate and an elastomeric composition
Method for editing a media clip in a mobile terminal device, a terminal device utilizing the method and program means for implementing the method
Polycarbonate resin composition and formed product thereof
Inkjet ink
Monofocal photographing lens assembly
Developing cartridge
Cardiopulmonary resuscitation monitoring apparatus
  Randomly Featured Patents
System and process for disposing of nuclear and other hazardous wastes in boreholes
Apparatus for measuring corrosion loss
Boot for motorcycling
Method for continuous on-site monitoring and treatment of water
System and method for optically tracking a mobile device
Needle free blood collection device with male connector valve
Virtual machine configuration system
Control of a permanent-magnet motor
Anti-alopecia composition
Vehicle lamp construction