What is TTL logic?

Thread Starter

Vladimir Tess

Joined Aug 29, 2007
6
Hey guys,

You see, I am reading this book, "digital electronics" -- the demystified version. Where I am reading is on section "Logic Gate input and Output". I've added here one of his page without permission (i gotta get this one), so can you please help me understand what he means by that diagram? How do these input gates work.

I understand the concept of NPN transistors.

Thanks much,

Vlad Tess
 

hgmjr

Joined Jan 28, 2005
9,029
I don't... know how to remove the zip file. I don't see any option to do so. Please admin, remove it for me.

Thanks.
I removed the attachment as you requested.

There is a means for you, the poster, to remove it as well. Just open your post up for "edit" that contains the attachment and select "advanced edit". You then scroll down to the "manage attachments" section and click on the "manage attachments" button. You will then get a window in which you will see a "remove" button. Click on the button to remove the attachment.

hgmjr
 

Newton1Law

Joined Aug 22, 2007
10
TTL Logic - Transistor Transistor Logic if this helps. It usually refers to the type of switchs (in this case transistor to transistor) used to obtain an output. AND gate, OR, NOR, NANAD, etc. In each case you are switching transistors from one state to another.
 
TTL Logic - Transistor Transistor Logic if this helps. It usually refers to the type of switchs (in this case transistor to transistor) used to obtain an output. AND gate, OR, NOR, NANAD, etc. In each case you are switching transistors from one state to another.
I will add to this;
It's a group of IC's used to perform digital functions. Some containing many logic gates, digital to analog converters Ect...

For example you can use the 7400 series of TTL IC's to build a digital clock like the one that wakes you up in the morning. :cool:
You can make all sorts of neat things with them.
 

Papabravo

Joined Feb 24, 2006
14,375
TTL was named by comparison to its predecessors DTL (Diode Transistor Logic) and RTL (Resistor Transistor Logic). In TTL you have both the input circuit built from transistors and the output circuit built from transistors. There are very few explanations extant on the multi-emitter transistors used in TTL logic input circuits. As others have noted it is possible to spend a whole career designing with these parts and never understand the operation of this part of the circuit. What is important to understand is that TTL inputs source current and you must pay attention to fan-out whenever an output has to drive more than a few inputs. CMOS circuits have largely eliminated such considerations, but have introduced a whole new range of gotchas.
 
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