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
Pharmaceutical composition comprising gabapentin or an analogue thereof and an .alpha.-aminoamide and its analgesic use
Pre and post-paid real time billing convergence system
Inter vehicle communication system
Door-activated entry light fixture
Generation of interpolated samples for decision based decoding
Low offset, fast response voltage controlled current source and controlling method thereof
Method and system for monitoring service quality in a mobile node
  Randomly Featured Patents
Patient lift
Thin polysilicon doping by diffusion from a doped silicon dioxide film
Picture encoding with wavelet transform and block area weights
System and method for finding desired results by incremental search using an ambiguous keypad with the input containing orthographic and typographic errors
Automotive performance meter
Seaplane with retractable twin floats
Adjustable tray and method of using the same
Elevator winding device
Antistatic hard coat film
Pipe connecting structure and cleaning tool