is a part of
a device that produces electricity; may have several primary or secondary cells arranged in parallel or series
is a part of
a cell containing an electrolyte in which an applied voltage causes a reaction to occur that would not occur otherwise (such as the breakdown of water into hydrogen and oxygen)
is a part of
equipment that involves the controlled conduction of electrons (especially in a gas or vacuum or semiconductor)
is a part of
electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
is a type of (narrower)
a device designed to transmit electricity, heat, etc.