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Thermocouples can be connected in series as thermocouple pairs with a junction located on either side of a thermal resistance layer. The output from the thermocouple pair will be a voltage directly proportional to the temperature difference across the thermal resistance layer and also to the heat flux through the thermal resistance layer.
A thermocouple (the right most tube) inside the burner assembly of a water heater Thermocouple connection in gas appliances. The end ball (contact) on the left is insulated from the fitting by an insulating washer. The thermocouple line consists of copper wire, insulator and outer metal (usually copper) sheath which is also used as ground. [33]
The Peltier effect can be considered as the back-action counterpart to the Seebeck effect (analogous to the back-EMF in magnetic induction): if a simple thermoelectric circuit is closed, then the Seebeck effect will drive a current, which in turn (by the Peltier effect) will always transfer heat from the hot to the cold junction.
Figure 2: [8] Working principle of a thermal laser sensor (Adapted from figure 3 with permission) As shown in Fig 2, a thermopile laser sensor consists of several thermocouples connected in series with one junction type (hot junction at temperature T 1) being exposed to an absorption area and the other junction type (cold junction at temperature T 2) being exposed to a heat sink.
Thermal fuses are usually found in heat-producing electrical appliances such as coffeemakers and hair dryers. They function as safety devices to disconnect the current to the heating element in case of a malfunction (such as a defective thermostat) that would otherwise allow the temperature to rise to dangerous levels, possibly starting a fire.
Heat sinks are often attached to portions of the circuit that produce most heat or are vulnerable to heat. Fans are also often used. Some high-voltage instruments are kept immersed in oil. In some cases, to remove unwanted heat, a cooling system like air conditioning or refrigerating heat-pumps may be required.
Polymers represent another large area in which thermal analysis finds strong applications. Thermoplastic polymers are commonly found in everyday packaging and household items, but for the analysis of the raw materials, effects of the many additive used (including stabilisers and colours) and fine-tuning of the moulding or extrusion processing used can be achieved by using differential scanning ...