posted by hamid on .
what is meant by the change go temperature of 1 degree celcius on the scale of a plantinum resistance thermometer
The length and diameter of the platinum wire used in a thermometer are often chosen so that the resistance of the device at around 0 ºC is 100 ohms. Such a sensor is a called a PT100 sensor, and its resistance changes by approximately 0.4 ohms per degree Celsius. Using a typical 1 mA measuring current, at around 0 ºC a PT100 sensor would have a voltage drop of around 100 mV across its terminals and this would change by approximately 0.4 mV per degree Celsius, which thus makes sensitive thermometry available to anyone with a high resolution voltmeter or resistance bridge. In many instruments the measurement is converted so that the reading is directly in temperature.
explain what is by a change in temperature of 1 on the scale of a platinum resistance thermometer