If you don't understand how does the logic gates works, this is the place you can find it. This guide also includes some useful combinations of Logic gates (like NAND, NOR etc...), so it is organized to two groups - Logic Gates and Logic Gates Combinations.
You can click on the gate's name to open up a page with detailed info about it. Every gate has its own slideshow showing its behavior.
This is part of the Logic elements guide. To see Logic gates combinations and flip-flops guide, go at this page.
Think of gates as a some kind of gate which only allows certain things to be let in. Gates can also be rotated by tapping on them and so their input and output areas change.
- This is the gate that has the letter "A" on it
- This gate requires the two signals on its side to be on
- Once both signals are on, the gate will transmit a signal from its top
- However, if only one signal is on or no signal is on at all, the gate will be off
Just to recap - AND Gate gives off a signal only if the first input is on AND the second input is on (explains the name "AND")
This is the gate with the "O" on it.
- It gives off a signal if either signal from its side is on
- Even if both signals are on, the OR Gate will still give off a signal
- However, if there is no signal at inputs, the gate does not give a signal
Just to recap - OR gates give off a signal if at least one of the inputs are on. OR Gate gives a signal if first OR second OR both inputs are recieving an electric current (explaining the name "OR")
This is the gate with "X" on it
- XOR Gates will gives off a signal if only one signal is on
- Unlike Or Gates, XOR Gates will turn off when both signals are on
Just to recap -
- XOR Gate is almost like the Or Gate except that it turns off when both are on
- X means exclusive
- It will turn on when one input is on but not both
This is the gate with the "N" on it
- This gate only has one input and that is at the bottom
- This gate inverts the signal (if the signal is on, it turns it off)
- And vice versa, if the signal is off it turns it off
You can string them together and if you know math or grammar well enough, two negatives negate each other (when in a positive operation)
Think of the childish not not not not ... thing. An even amount of Nots make a positive while an odd makes things negative.
Like in this example - two NOT gates negate each other, so the final output will be the same as input.
OK, another recap -
- A NOT gate will turn the signal to the other state ( i.e. on to off, off to on - explains the name "NOT")
- These gates can be chained together
- If the circuit has an even number of not gates then it just negates itself
- This is useful for compacting circuits.
- If the chain has an odd number of gates then it functions as a normal not gate would.
This is the gates with "D" on it
- This gate uhh.... delays a signal.
- This gate also has one input.
- This gate delays the circuit for 0.25 seconds
Delay Gates can be also chained -
- the "chained" means that the gates don't have any spaces between them
- when chained, the delays are - 1sec (two gates), 4secs (three gates) and 7secs (four gates). 7secs is max delay, after it will count again from 0.25sec (and then 1sec...)
If you wonder why, the rule is - the delay gates looks how many delay gates are directly preceding it. When 0 it delays 0.25sec, when 1 it delays 0.75sec and when 2 or more it delays 3secs.
And an example of the how to get 0.4, 0.6, 0.8, etc.
We now know that delay gates delay ON signals but did you know that delay gates also delay the OFF signal? They delay the off signal by the same amount of time they would with the on signal.
- A Delay gate delays a signal (explaining the name "delay")
- The Delay Gate delays the on signal and the off signal
- They can also be chained to produce longer delays but only up to 7 seconds
It is the gate that has random looking scribbles on it
- It gives off a signal at a random interval on a random length
- It has something called a clock input
- But you don't need to connect the clock input in order for this gate to work
Time to Recap -
- Random Generator makes random currents with random lenght (explains tye name "random")
- It has something called a clock input