Position: Index > Sensor Circuit >

2N222 Transistor As Temperature Sensor

2014-11-05 02:55  
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.

This is a simple Electronic thermometer circuit. This is a inexpensive circuit because probe or sensor that is used in this circuit is 2N2222 silicon transistor. The accuracy of this circuit is better than 1°C over a 100°C range. The input voltage of this circuit is regulated to 1.2V by the LM113 diode. This voltage is used to set operating current of the temperature-sensing 2N2222. Here is the schematic diagram of the circuit:

Electronic thermometer circuit schematic diagram
The feedback resistor R5 is used to calibrate the output scale factor to 100mV/°C. The amplifier output is biased for zero at 0°C by the R4. So, the scale factor does not change to zero when the output is zero. [Circuit's schematic diagram source: seekic.com]




Reprinted Url Of This Article:
http://www.simplecircuitdiagram.com/2010/12/10/2n222-transistor-as-temperature-sensor/