To implement Boolean functions, designers use electronic gates. Because they function on simple logical operations, they are commonly stylized as ‘logic’ gates. These gates are incredibly common and feature excessively in our day to day life. From mobile phones to washing machines, everything has logic gates in them!
Today we will be looking at the seven essential logic gates in order to establish their importance.
The Three Basic Logic Gates:
The AND Gate:
The appropriately named AND gate returns a result of 1 when the first AND the second input are both 1. On every other instance, the output is always 0, as illustrated by the following truth table.
The OR Gate:
As its name suggests the OR gate gives an output of 1 when any of the 2 inputs (or both) are 1. The only instance in which you can get an output of 0 is when both the inputs are 0, as seen in the following truth table.
The NOT Gate:
The NOT gate is the simplest logic gate to understand. When the input is high, the output is low and when the input is low, the output is high.
The Two Derived Gates:
Now that we’ve looked at the three basic logic gates, it’s time we turn our attention to gates that are derived from a combination of these gates.
The NAND Gate:
The NAND gate is a combination of the AND gate and the NOT gate which means that the output of this gate is the exact opposite of the AND gate, as seen in the following truth table.
The NOR Gate:
The NOR gate can be thought of as the summation of the OR gate and the NOT gate. The final result is the exact opposite of the OR gate as the following truth table shows.
The Two Exclusive Gates:
The XOR Gate:
The exclusive OR operates in a similar fashion to the OR gate. The output is 1 if either of the (but not both of the) inputs are 1. This can be better understood by a truth table.
The XNOR Gate:
The exclusive NOR operates is just a summation of the XOR gate and the NOT gate. This means it functions exactly opposite to the XOR gate, as seen from the following truth table.
Applications of Logic Gates:
Now that we know how logic gates work, let’s look at a few practical examples of where we can find them in practical life.
Street Lights:
Have you ever noticed how street lights turn ON as soon as it gets dark and switch off as soon as its dawn? That’s because these lights have light sensors coupled with a simple NOT gate. These light sensors or light-dependent resistors give an output of 1 when it’s bright and an output of 0 when it’s dark.
If this output was to be directly fed to the street light, these lights would be ON throughout the day and turn OFF as soon as it gets dark! By feeding the output of a LDR to the NOT gate, we can automate them properly to ensure they operate only when it’s dark. This is much friendlier on the environment as it saves energy!
Automatic Fan Control System:
You can design a simple emergency fan system that operates as soon as it gets hot during the daytime by coupling a heat detector with an LDR via an AND gate. During daytime, the LDR will give an output of 1 but the fans won’t operate if it’s not excessively hot.
However, if a machine is getting overworked and giving off a lot of heat, the heat detector will give an output of 1. Now the two inputs of the AND gate are 1 so the fans will operate!
Where to Buy Logic Gates:
Logic gates are ridiculously common and can solve most of your circuit problems and needs. If you’re looking for high quality and reliable logic gates, then we at ADSANTEC would love to be of service to you. We have a wide collection of high-speed logic gates that can operate at extremely high frequencies. Get in touch with us today to learn more about our amazing products.