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
Semiconductor IC including pulse generation logic circuit
Adaptive switch mode LED system
System and method for updating firmware
Power supply input voltage detection circuit
Systems and/or methods for using air/wind power to charge/re-charge vehicle batteries
Quantifying the risks of applications for mobile devices
Semiconductor device comprising a Fin and method for manufacturing the same
  Randomly Featured Patents
Low pressure mercury vapor discharge lamp
Fuel saving apparatus and method for textile drying and finishing
Semiconductor device having conducting material film formed in trench, manufacturing method thereof and method of forming resist pattern used therein
Knife head, particularly for polygonal turning machines
IL-13 receptor antibodies
Multi-layer pneumostoma management system and methods for treatment of chronic obstructive pulmonary disease
Aircraft autothrottle system
Patterned woven fabric
Controlled release lipoic acid
One-piece bridge for connecting modular units