Table of Contents
Why is a thermocouple used in RF measurement of current?
It is used for both the AC and DC measurement. The current whose magnitude is used to be measured passes through the junction of the thermocouple. The current produces the heat in the heater element, and the thermocouple induces the electromotive force in the output terminals.
What are the limitations of thermocouples used in RF ammeter?
Limitations of Thermocouples: A rise in temperature (higher operating temperatures) causes a change in the resistance of the heater. Presence of harmonics changes meter reading, because the heating effect is proportional to the square of current.
What is the principle and operation of a thermocouple type RF ammeter?
Thermocouple generates an EMF, e, whenever the Alternating Current, I flows through heater element. This EMF, e is directly proportional to the rms value of the current, I that is flowing through heater element.
Which type instrument which used the thermocouple for the measurement of the temperature?
thermocouple, also called thermal junction, thermoelectric thermometer, or thermel, a temperature-measuring device consisting of two wires of different metals joined at each end. One junction is placed where the temperature is to be measured, and the other is kept at a constant lower temperature.
What is RF ammeter?
The Transformer Coupled Ammeter (TCA) series of RF Ammeters provides AM broadcasters with an accurate and reliable instrument for measuring common point and antenna base currents. The ammeter uses a toroidal current transformer to obtain a sample voltage proportional to the RF current flowing in a conductor.
What is a thermocouple used for?
Thermocouples are used in applications that range from home appliances to industrial processes, to electric power generation, to furnace monitoring and control, to food and beverage processing, to automotive sensors, to aircraft engines, to rockets, satellites and spacecraft.
Does ammeter measure current?
ammeter, instrument for measuring either direct or alternating electric current, in amperes. An ammeter can measure a wide range of current values because at high values only a small portion of the current is directed through the meter mechanism; a shunt in parallel with the meter carries the major portion.
What are the advantages of a thermocouple thermometer?
Advantages:
- The thermocouple is less expensive than RTD.
- It has wide temperature ranges.
- It has good reproducibility.
- The temperature range is 270 to 2700 degree Celsius.
- It has rugged construction.
- It does not required bridge circuit.
- It has good accuracy.
- It has high speed of response.