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
Pressure-applying member, fixing device, and image forming apparatus
Chemically bonded carbon nanotube-polymer hybrid and nanocomposite thereof
Shoe
Internal wiring structure of semiconductor device
Adapter
Toothbrush holder
Medicament delivery device and a method of medicament delivery
  Randomly Featured Patents
Substituted vinyl pyridine derivative and drugs containing the same
Valves incorporated structure in a tension adjusting cylinder body for a crawler type vehicle
Non-rotatable elastomeric O-ring seal
Vehicle brake control device
High-speed internal clock synchronizing method and circuit
Rice hybrid XL745
Method and apparatus for detecting quenching of a coil for a superconducting magnet
Medical equipment overhead mounting structure
Elastomeric composition
Apparatus for testing a pulsed light oximeter