Complementary Metal Oxide Semiconductor

It is used in Microprocessors, Microcontrollers and many electronic digital logic circuits. It is a semi-conductor chip that keeps data without requiring any external power source. This technology uses both N-type and P-type transistors , they both are used to conclude logic functions. CMOS technology is a semiconductor technology for latest microcontrollers such as 8051,8052 microchips. There is Low Power Consumption. In Vocabulary of Processors CMOS keeps the major instructions the computer requires to initialize its hardware components and boot up. There is High Noise Immunity in these type of devices that is No effect of High Noise. It uses both N Type and P type transistors.

In the figure above (CMOS inverter) when the voltage of input X is low NMOS transistor has high resistance while PMOS has low resistance and it allows voltage source to transfer voltage through PMOS transistor to output which is generally high voltage.

The main point of CMOS over NMOS and bipolar technology is the much smaller power usage then them. This allows to integrate many more CMOS gates on IC than in NMOS or bipolar technology, resulting in much better performance. Unlike NMOS or bipolar circuits, a CMOS circuit has almost no static power dissipation

e.g CD4001, CD4002, CD4025