Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

a diode is an electronic component with two electrodes (connectors) that allows electricity to go through it in one direction and not the other direction.
diode

karl mannheim (27 march 1893 - 9 january 1947), or károly mannheim in original writing of his name, was a hungarian-german sociologist and social scientist.
karl mannheim

musa ibrahim is a bangladeshi mountaineer and a journalist.

musa ibrahim