Logic Gates (Truth tables)The Following are Truth Tables to some of the most common logic gates. By learning these you will be able to work through a very large circuit that may use many logic gates. By doing this you will be able to understand and make very complex 'logic' circuits. Information is fed into a logic gate via logic signals. These signals either being logic 0 (off) or logic 1 (on). Some Logic Gates are different versions of the basic logic gates, these have the letter 'N' before the name, e.g NAND. The N stands for Not and this will reverse all the values at the output. So 1,1 at the input of an AND gate will produce a logic 1 signal at the output. In a NAND gate the logic 1 will be changed to logic 0.
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The 'OR' Gate
The 'OR' gate will give a logic 1 output if Input A or B is logic 1. |
The 'AND' Gate
The And Gate will give a logic 1 output signal if Input A and B are both at logic 1. |
The 'NOT' Gate
The NOT Gate is also known as an invertor, it will give an output signal that is opposite to that at the input. I.e a logic 1 signal at the input will give a logic 0 signal at the output. The Schmitt trigger is another component that is very much like the NOT gate, it will invert the Input signal. However it unlike the NOT Gate it will also 'smooth' the input signal, so a 'noisy' input signal will be cleared out. |
