8051 is one of the first and most popular microcontrollers to become available in the market. Developed by Intel in 1981, this microcontroller has gone on to be a staple in various engineering fields. Initially, the 8051 came out as an N-type metal-oxide-semiconductor (NMOS) based microcontroller. This type of technology uses n-type transistors. With NMOS, a single transistor is used for each logic gate within the microcontroller, resulting in fewer parts and simpler circuitry than what you would find with other technologies at that time. The downside to NMOS is that it requires more power than some other types of technology and can be susceptible to noise issues due to its low input impedance caused by the n-type transistors. As advancements were made throughout the years, later versions of 8051 were based on complementary metal-oxide-semiconductor (CMOS) technology. CMOS operates on two principles: depletion and enhancement modes which allow for transistors to switch between ‘on’ and ‘off’ states. CMOS provides higher speed performance while consuming less power than NMOS, making it possible for microcontrollers like 8051 to run faster without using too much energy