Consists of a Peltier element made of 127 series connected semiconductor rods, mounted on a heat sink. The Peltier element connects via a switch to either two 4 mm safety sockets (position Peltier effect) or a small motor with a propeller (position Seebeck effect).
Peltier effect: The sockets are connected to a power supply (max. 8 V and 3 A). When current flows through the element, a temperature difference arises between the two sides of the element. The sign depends on the direction of the current. (The switch must be placed in position Peltier effect.) NOTE: If the black socket is connected to plus, the free side of the Peltier element is heated. Do this only for a very limited time! The element is damaged by high temperatures.
Seebeck effect: If on the other hand a temperature difference exists between the two sides of the element, a voltage is created. You can demonstrate this immediately by watching the motor with the switch in the Seebeck effect position. If you want to connect an external load and possibly measuring instruments, the switch must be in position Peltier effect – it is nonetheless still the Seebeck effect that is investigated.
The free side of the Peltier element can readily be heated or cooled using a beaker with hot resp. cold water, which will create a voltage across the element.