A thermopile generates electricity from the heat of a pilot light. It generates about 750 mV that turns on the main gas valve to the fireplace.
A thermocouple is heated by the pilot light but it uses pressure to hold the pilot light gas supply valve open. When the thermocouple is heated, pressure increases holding open the main gas valve. If it cools down, the pressure goes down and closes the gas valve.
No, as the voltage of a single thermocouple is very low , you need a thermopile (thermocouples connected together) and a circuit to get a readable voltage at the other end.
to detect radiation
I am assuming that you mean switching a millivolt gas value. The switch applies a voltage to the gas valve thus allowing gas to flow. The voltage is provided by a thermopile. This device transforms the heat from the pilot into a voltage that can be used to control the valve. This system does not require an external voltage source. It does require the pilot to continuously operate. A thermopile consists of a number of thermocouples that are wired in series. This allows an increase in the voltage that would be provided by a single thermocouple.
Yes.
The output of the thermocouple is linear.
thermopile
thermopile
Yes, thermocouple is used in fridges !
To create a thermocouple one needs thermocouple wire, a means of spot welding the wire, and wire strippers. A thermocouple is used to measure temperature.
The thermocouple keeps a gas pilot light burning.
is a thermocouple an active or passive transducer?-why?
You should not paint a thermocouple.