102 Flashcards
What is a truth table?
> This is the possible output combinations based off all the possible inputs, collated in a table
What is required for an AND gate to equal 1?
> When both inputs are 1
What is required for an OR gate to equal 1?
> When either of both inputs are 1
What is required for an NOT gate to equal 1?
> Then the single input is 0
What is required for an NAND gate to equal 1?
> The output will be 1 as long as both inputs are not 1
What is required for an NOR gate to equal 1?
> When both inputs are 0
What is a buffer? What are their uses?
> This is a component with one input where the output is the same as the input
Used in amplifier circuits
What is required for an XOR gate to equal 1?
> Either inputs must be 1 but not both
What is required for an XNOR gate to equal 1?
> Either
What are the symbols for: AND OR NOT NAND NOR XOR and XNOR
AND: y = a.b OR: y = a+b NOT: y=a ̅ NAND: y=a.b ̅ NOR: y=a+b ̅ XOR: y=a⨁b XNOR: y=a⨁b ̅
What are logic levels?
There are 2 levels represented by 0 (low) and 1 (high)
Are all logic levels the same? Explain?
No, the levels of the logic levels are based off different industrial standards for different manufacturers
What are each of the logic levels called? What do they mean?
> VOH(min): The lowest guaranteed voltage from an output that would correspond to a high
VOL(max): The highest guaranteed voltage from an output that corresponds to a LOW
VIH(min): The lowest voltage that an input will guarantee to register as a HIGH
VIL(max): The highest voltage that an input will guarantee to register as a LOW
What can be said about the values for VIL & VIH when compared with VOH & VOL
> The accepted range for the inputs is often larger than for the output, this is known as a noise margin
What are the 2 main facilities of logic levels and their different types?
> TTL ( Transistor-transistor logic): 5VTTL and LVTTL
> CMOS (Complementary Metal-oxide semiconductor): 5V CMOS, LVCMOS and there is also 2.5V CMOS and 1.8V CMOS
