Position: Index > Linear >

Inexpensive Linear Thermometer

2017-03-17 09:34  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.

As a sensor in the design of this linear thermometer, the LM34 is used. The output is the difference between
Inexpensive Linear Thermometer

two base-emitter voltages AVeb ?°f two transistors operated at different collector-current densities. where the current densities are IC and let, k is Boltzmann`s constant, and q is the electron charge. Because all factors, including the ratio IciUci are constant, the output of the LM34 (National Semiconductor) is a linear function of in the range over - 50?° to 300?°F, which provides the output voltage of 10 mV/ ?°F with a max. nonlinearity of ?±0.35?°F. The output of the LM34 is amplified by a three-op-amp instrumentation amplifier. The fourth op amp gives the possibility to control the offset voltage of the amplifier. The gain A of the instrumentation amplifier can be set to any desired value by the choice of the resistance R2 only.

Reprinted Url Of This Article: