Use externally calibrated Digital thermometer to calibrate digital display thermometer.

• For 2-8 degree
• keep the beaker full of water in refrigerator 24 hours before the calibration.
• At the time of calibration, keep all the thermometer along with calibrated thermometer inside the the beaker.
• Keep beaker in refrigerator. After 15 minutes note the reading.
• For 0-30 degree
• keep all the thermometer along with calibrated thermometer inside the beaker full of water.
• keep it in deep freezer for 4-5 hours or until water get freezed. note the readings.
• For > 25 degree
• keep all the thermometer along with calibrated thermometer inside the beaker full of water.
• keep it at room temperature for 1 hour. Note the readings.

Enter all the data in XL sheet. Note the difference between observed value and nominal value(calibrated thermometer value), which should be less than 2 degree. Note down the difference on display thermometer. Note the calibration data in LIS. and calibrate every 6 months.