Published:2009/7/20 6:08:00 Author:Jessie | From:SeekIC
Thermistor thermometer that can be calibrated for two temperature ranges. If another meter is used in place of the one specified (1500 ohms) the resistance of M plus R5 should equal 5350 ohms. To calibrate for the 32°F to 122°F scale immerse R3 in crushed ice and adjust R4 for zero current; mark the location of R4's knob pointer. Replace R3 with the low-resistance test resistor supplied, and adjust R7 for full-scale deflection; mark R7's position. Save the low-resistance test resistor. This completes the 32°F to 122°F calibration. To calibrate for -40°F to +32°F replace R3 with the high-resistance test resistor supplied, and adjust R4 for zero current; mark R4's location. Replace the rest resistor with R3. Immerse R3 in crushed ice, and adjust R7 for full-scale deflection; mark R7's location. This completes the -40° to +32°F calibration (courtesy General Electric Company).
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