Logic how does it work

An AND logic gate with two inputs and one output. In this example, our chicken and rooster are not dependent on each other, so if a chicken OR a rooster approaches our gate, we will open it for them. With an OR gate, you only need one of your inputs to be a 1 for the output to also be a 1.

The pattern here is also pretty clear as well. Both of our inputs are not dependent on each other, and so long as one of them is present, our gate will open. If you want to quickly identify an OR gate on a schematic, look for this symbol:. An OR logic gate which only requires one input to be 1. Despite our goat representing a 1 in our logic gate as an input, a NOT gate always produces an opposite output. NOT gates are a bit strange when compared to other gates, as they always do the complete opposite of whatever input value you provide it.

These gates also only require one input to produce their output, whereas other gates will always need two inputs. A NOT logic gate provides the opposite of its input value as its output. For example:. And to put a XOR gate on a schematic, be on the lookout for this symbol:. And if the inputs are different, they output will be 0, or false. For our chickens, we can use an XNOR gate to open our gate only when a chicken and rooster pair journey out together, or if there are no chicken or roosters together.

An XNOR logic gate only returns a 1 output value if the two inputs are the same. A NAND gate is just what we need to make this happen:. A NAND logic gate returns an output of 0 when both inputs are 1. Our last and final gate to work with on our farm is a NOR gate, which is just like a NAND gate in that it has an opposite output than you might expect. The NOR gate is just what we need:. This prevents them from ever improving. People use words like "logic" and "logical" a lot, often without really understanding what they mean.

Strictly speaking, logic is the science or study of how to evaluate arguments and reasoning. It's not a matter of opinion, it's a science of how arguments must be formed in order to be reasonable or correct.

Obviously, a better understanding is critical for helping us reason and think better. Without it, it's too easy for us to fall into error. The term "critical thinking" is used often but it isn't always properly understood. Put simply, critical thinking means developing reliable, rational evaluations of an argument or idea.

Critical thinking is a means for separating truth from falsehood and reasonable from unreasonable beliefs. It frequently involves finding flaws in the arguments of others, but that's not all that it's about. It's not simply about criticizing ideas, it is about developing the ability to think about ideas with greater critical distance. Arguments are about disagreement - people aren't likely to argue over things they agree on.

As obvious as that may be, it isn't always as obvious what, exactly, people disagree on. This is especially true for those who are caught up in the midst of a disagreement. This is a problem because disagreements can't be resolved if those involved don't recognize what their disagreement is really about - or worse yet, actually disagree on what they disagree about. If those involved don't work that out, the only thing they'll accomplish by arguing is to create more animosity.

Propaganda is any organized, coordinated effort to convince masses of people to adopt some particular idea, belief, attitude, or viewpoint.

It's easiest to see government propaganda in the context of wartime. The label is also applicable to the efforts of corporations to buy their products, to apologists trying to get people to adopt their religion and many other situations. Understanding the nature of propaganda and how it works is critical to being able to think more critically about it. Actively scan device characteristics for identification.

Use precise geolocation data. Select personalised content. Therefore the base and emitter voltages on T4 are approximately equal, so T4 will be turned off. If either one of the inputs is taken to logic 0 however, this will make T1 conduct, as the emitter that is at logic 0 will be at a lower voltage than that supplied to the base by R1. This will cause T1 to saturate, taking its collector to a low potential less than 0.

However, sufficient current will be flowing out of the output terminal feeding the next gate input circuit to cause T4 emitter to be held at about 4. This is 0. This places about 4V or logic 1 between 2. CMOS ICs can operate from a wide range of supply voltages typically 3 to 18V, and lower with some sub families , with very low power consumption. Fig 3. T1 and T2 are connected in parallel from supply to the output X, so switching either of them on will result in a logic 1 at output X.

T3 and T4 are connected in series between X and ground so when both are switched on, a logic 0 will appear at output X. The eventual logic state at X depends of course on the on or off state of the combination of all four transistors, and these are controlled by the logic states applied to the inputs A and B as can be seen in Table 3. Logic 1 on input A reverses this condition. Logic 1 on input B reverses the condition.

To minimise such damage and protect the gates from any high voltage static electricity spikes that may appear across the IC during handling, CMOS ICs should always be stored in anti static packaging, and handled in accordance with manufacturers handling procedures.

To protect the ICs from high voltage spikes when in circuit, protection diodes see Fig. Similarly, if a negative voltage appears at input A, D4 will conduct, limiting the input voltage to no less than 0V.

Input B is protected in a similar manner by D1 and D2. Note however, that although the diodes offer protection, it is still possible that very large static voltages may still damage these devices, so anti-static precautions should always be used when handling CMOS devices.