Until 1971, the known three fundamental electrical elements
were resistor, inductor, and capacitor. In 1971, Professor Leon
Chua proposed theoretically a fourth fundamental electric
element, and he called it “Memristor." Memristor is a twoterminal element whose resistance depends on the magnitude,
direction, and duration of the applied voltage. This element is
realized later by HP labs in 2008, which opened a wide area of
research on the memristor and its possible applications. This
paper gives an overview of the device properties, fabrication,
modeling approaches of the memristor and some possible
future improvements. The paper also surveys the digital and
analog applications of memristors, and possible future
improvements in some applications