Light switch models show the operation of CMOS inverter and NOR logic gates. Now we look at the circuit symbols and schematic diagrams for these models. The NMOS and PMOS transistor symbols show the insulated gate, and the source and drain terminals connected.
For the inverter, the PMOS transistor is connected between the power supply and the output, and the NMOS transistor is connected between the output and ground. The two connected gates are the inverter input, and the connected drains are the output.
For the 2-input NOR logic gate, two PMOS transistors are connected in series between the power supply and the output, and two NMOS transistors are connected in parallel between the output and ground. Two pairs of connected gates serve as the NOR inputs.
The truth table shows that when inputs a and b are both 0s, or both 1s, the NOR circuit works just like an inverter. When the two inputs have different values, one PMOS transistor is shut off, cutting off the power supply connection, and one NMOS transistor is turned on, forcing the output to 0.
The NAND logic gate is like the NOR, except that the PMOS transistors are connected in parallel instead of in series, and the NMOS transistors are connected in series instead of in parallel.
This is the last video in a series on CMOS technology:
CMOS Tech: NMOS and PMOS Transistors in CMOS Inverter
• CMOS Tech: NMOS and PM...
CMOS Inverter Model Using Light Switches
• CMOS Inverter Model Us...
CMOS NOR Logic Model Using Light Switches
• CMOS NOR Logic Model U...
CMOS inverter, NOR, and NAND Schematics, Models Using Light Switches
• CMOS inverter, NOR, an...
12 сен 2024
