# TTL - Is there a logic gate or IC that does this?

• grimofdoom
In summary, this summer I plan on taking a long break from my arduino and learning some more 'ancient' and fun stuff. I plan on learning to use and make different circuits using TTL's. I have read a bit on it and learned on the basic logic gates like(using '/' as separator for the reverse) n/and,n/or. There is one kind of logic gate I'm curious about(this is something I've made on minecraft and if it works irl with logic gates).Question:Is there a logic gate or IC that (uses 2 inputs and 2 outputs) when line A is high, line
grimofdoom
So this summer I plan on taking a long break from my arduino and learning some more 'ancient' and fun stuff. I plan on learning to use and make different circuits using TTL's. I have read a bit on it and learned on the basic logic gates like(using '/' as separator for the reverse) n/and,n/or. There is one kind of logic gate I'm curious about(this is something I've made on minecraft and if it works irl with logic gates). Question:

Is there a logic gate or IC that (uses 2 inputs and 2 outputs) when line A is high, line B will never be(and reverse). No matter what you put into line (off), if will produce no output.

This would be a really useful piece for my first project I am planning for the summer. I plan on making a battery powered Tic Tac Toe game. I haven't started yet and am going to start drawing up a sheet(don't remember what they are called, it's a drawing on how the entire thing is connected and where) for what I am going to build.

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Please show us the truth table for the device you are trying to describe.

A= wire 1
B= wire 2
C= which was active first

A B C | OutPut-A output-B
1 0 A| 1 0
1 1 A| 1 0
0 0 0| 0 0
0 1 B| 0 1
1 1 B| 0 1

I have not made a truth table before, so This may be a little rough

TTL is very high power.
Direct CMOS equivalents to TTL gates are available in the 74HCxx series.

I would strongly suggest you experiment with low power 4000 series CMOS rather than TTL gates.

Baluncore said:
Your logic function looks like a JK flipflop.
http://en.wikipedia.org/wiki/Flip-flop_(electronics)#JK_flip-flop

I don't think a flip-flop really suits his purpose. Or at least not by itself. He wants two separate outputs(I assume to drive different color LEDs), not a Q and Q'.

Considering you want to make a Tic-Tac-Toe game, I think you are best off doing the whole thing in code. Handling resets will be much easier. If you really wanted to use discrete logic gates, you could combine flip-flops with tri-state buffers. But I don't know of a simple logic device that does what you are looking for.

I want to break away from my arduino and learn more off hand stuff so I don't spend as much time and memory on my arduino

This statement "C= which was active first" does not make a lot of sense in logic like this - do you mean " the input that went high (1) first" or " the one that changed state first" -- these inputs are not "active" they are always 0 or 1 -- both states are equivalently "active".

Sorry, it does sound unusual and not right, I did mean High/1.

grimofdoom said:
So this summer I plan on taking a long break from my arduino and learning some more 'ancient' and fun stuff. I plan on learning to use and make different circuits using TTL's.
Hmm. I started my "ancient' logic learning with RTL.

I still use RTL...

A simple RS Flip/Flop made from NAND gates with output inverters will satisfy the logic table presented.
See attached.

#### Attachments

• RS_NAND_FF.jpg
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I may be a bit confused,but a nand gate sends a 1 as long as there is a 1 on an input. The diagram(above), how I am reading it is that as long as one is 1, the other will also return a 1(which I am looking for a reverse where if one is 1, the other will always return a 0)

This is where I looked up nand logic gate btw. http://en.m.wikipedia.org/wiki/NAND_logic

A NAND gate sends 1 except when both inputs are 1.

With 00 as inputs, the two NAND gates both send 1. When input goes to 1, the corresponding NAND gate goes to 0, which keeps the other NAND gate at 1 regardless of what the other input does.

Sorry, I'm probably getting confused somewhere. I keep seeing this and see that nand let's there be a 0 when there is both inputs 1. Am messing myself up somewhere?

thats right. did you forget about the inverting gates at the end of Baluncore's circuit?

Ok, I have not seen that symbol before (and I took a huge step when asking this question), but I'm guessing the diode triangle with open ball inverts a 1 making it a 0 instead?

Niggle: A diode symbol is a triangle with a bar across the output point.

A triangle by itself, with only two leads, is a "buffer" or a "yes gate"
... the output is logically the same as the input. H>H, L>L.

An open circle on the output of any gate inverts the output - i.e. a nand gate symbol is an and gate with an open circle on the end.

Thus a buffer with an open circle takes the input and returns the opposite... as you have correctly surmised.
This is called an "inverter" or a "not gate".

So when the inverter get a 0, does it pull electricity from a Separate line to invert that 0 to a 1?

all the logic gates do. Those symbols are an abstraction.

Yes. Logic gates need power supplies, 0V and +5V supply rails were once very common as that was specified for TTL.

For experimentation, 4000 series CMOS will operate on anything between 3V and 15V.
http://en.wikipedia.org/wiki/4000_series

Alright, thank you. This will al be very useful

SMD needs miniature solder pads to Surface Mount on a PCB. DIP have two rows of big pins that will go through PCB holes or into sockets.

Get an experimenters breadboard and begin with a few DIP logic gates.
Examples …
http://www.jaycar.com.au/productView.asp?ID=PB8814
http://www.jaycar.com.au/productView.asp?ID=PB8816

Darnit. So I'll have to pass on that. Do you know of anywhere/thing I can purchase that contains DIP logic gate ic chips of different kinds?

Find a copy of the “CMOS Cookbook” by Don Lancaster; or the “TTL Cookbook” by Don Lancaster.
There are many pdf copies around, or visit your local library.
If you like it there are new and used copies available. Find them through bookfinder.com

Choose your chips from the CMOS Cookbook or from this list.
http://en.wikipedia.org/wiki/List_of_4000_series_integrated_circuits

Digikey
Mouser
RS Components
Farnell / Element14 / Newark

There are many other suppliers. You will probably have a local retail outlet.

I was planning on wanting to do a single purchase of like a grab bag or kit of some sort.

There are often local suppliers who cater to the hobby market - but you have to look around for them.
Try the yellow pages under electronics supplies and look for "hobby".

In Australasia, an outfit known a "Dick Smith Electronics" can be good for this, they make kits too.
There used to be many more. I used to get my components from workshops who repair radios... but I was a kid back then and could get away with hanging around the back doors of these places asking questions until someone gives me something to do.

However, ICs are usually not sold in "grab bag" style where you get a range in one package.
You have to tell them what you want and how many you need.

In a pinch you can sometimes order from the manufacturer.

Nice to hear the CMOS cookbook is still around ... it is really good value.

"Dick Smith Electronics" have moved out of electronic components and kits.
DSE has been largely replaced in .au by “Jaycar” who sell components and kits …
http://jaycar.com.au/
@ Simon Bridge. There are Jaycar dealers now on both sides of the Tasman.

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Logic circuits are pretty easy to work with, in addition to the TTL ICs, a breadboard, and a 5V power supply - you need to be able to control inputs and "see" outputs - so SPST switches, push buttons, LEDs and resistors.

You will find that the ICs and LEDs have smoke in them - that is normal, but once the smoke is let out, the device is dead.

Also there appear to be some pretty good Logic Circuit Simulators on the web- they are typically smoke free.

Baluncore said:
"Dick Smith Electronics" have moved out of electronic components and kits.
DSE has been largely replaced in .au by “Jaycar” who sell components and kits …
http://jaycar.com.au/
@ Simon Bridge. There are Jaycar dealers now on both sides of the Tasman.
Oh cool.

There is a DSE in Auckland that still does the hobby-components market ... obviously they are just doing it on their own. But thanks - it's been a while since I did any serious hobby electronics.

## 1. What is TTL and how does it work?

TTL stands for Transistor-Transistor Logic and it is a type of digital logic circuit that uses transistors to implement logic gates. It works by using the voltage levels of the input signals to determine the output signal.

## 2. Is there a specific logic gate that performs TTL?

Yes, there are several logic gates that can perform TTL, including AND, OR, NOT, NAND, and NOR gates. These gates use transistors to implement the TTL logic.

## 3. Can I use an IC to perform TTL?

Yes, there are many Integrated Circuits (ICs) that are designed specifically for performing TTL logic. These ICs contain multiple logic gates and can be used to implement complex digital circuits.

## 4. What are the advantages of using TTL logic gates?

TTL logic gates are known for their high speed and low power consumption. They are also relatively inexpensive and widely available, making them a popular choice for digital circuits.

## 5. Are there any limitations to using TTL logic?

One limitation of TTL logic is that it is not suitable for high-speed applications, as it can only operate at a maximum frequency of a few megahertz. Additionally, TTL circuits can be sensitive to noise and may require additional circuitry for noise suppression.

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