Gas Heat ESCO Practice Exam

A good thermocouple should read approximately ____ on a D.C. meter

1. 10 millivolts (mV)

2. 20 millivolts (mV)

3. 30 millivolts (mV)

4. 40 millivolts (mV)

The correct answer is: 10 millivolts (mV)

A good thermocouple typically produces a voltage output that is proportional to its temperature differential, and the readings are generally in the millivolt range. While the output voltage can vary depending on the type of thermocouple and the temperature it is measuring, a reading of around 10 millivolts is typical for many standard thermocouples at lower temperature differences. Thermocouples operate on the principle of the Seebeck effect, where a voltage is generated at the junction of two different metals when there is a temperature difference. For many common thermocouple types, such as K, J, or T types, the output is often close to 10 mV for a specific temperature range. Understanding the specifics of the thermocouple type and the conditions under which it operates is essential, as higher temperatures might yield greater millivolt outputs, but for a good thermocouple under standard conditions, around 10 mV is an accurate benchmark. This reliability makes it an important standard in diagnostics and measurements involving thermocouples.