'Vaiseshika' 41/2 Digits Digital thermocouple Test Set and Calibrator Type 7709 is a versatile equipment in the area of thermal engineering. The instrument is ideal to calibrate potentiometric recorders, platinum resistance thermometers, temperature controllers and recorders. The instruments can also be used as a thermocouple simulator with an accuracy of ± 0.02%. A calibrated stable potential source, continuously variable from 0 to ± 100 mV, is provided with the test set. The potential variation can be done with a resolution of 10µV. Similarly thermo-e.m.f, generated across a thermocouple, in a furnace, can be monitored with Digital Read Out Display in this instrument with an accuracy of ± 0.02%. Provisions for current measurement and current simulation for the calibration of standard transducers, current loops and process control instruments are additionally provided in the instruments type : 7709 C. A standard Wheatstone Bridge is also provided with the test set. The resistance ranging from 0.1 ohm to 100 ohm can be measured and simulated with an accuracy of ± 0.1%. The additional facility is provided to use the bridge as Standard Decade Resistance Substitution Box of accuracy ± 0.1%. The Wheatstone Bridge and Decade Resistance Box section can be used for the calibration of Platinum Resistance Thermometer and measurement of thermocouple resistance. Vaiseshika" 41/2 Digits Digital thermocouple Test Set and Calibrator Type 7709 is a very good substitute for the traditional bridge type thermocouple test set which is cumbersome, complicated and time consuming. This instrument is convenient and provides direct reading facility in terms of LED display of bright red colour.