Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
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Is it worth it learning how to use 7400 series "jelly bean" logic IC's or are they completely obsolete?
My road map for learning electronics included the 7400 series logic chips. I started in on electronics by following the labs in the "Art of Electronics" lab manual which includes labs with ...
- 1,745
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What are the advantages of using FPGAs over TTL in intro computer architecture?
I teach the one and only computer architecture course at a liberal arts college. The course is required for the computer science major and minor. We do not have computer engineering, electrical ...
- 1,609
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answers
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What does a two overlapping circles symbol mean in an electrical schematic/diagram?
In the datasheet for a A3503 Hall Effect Sensor, I saw a circuit diagram labeled 'Functional Block Diagram', and it shows a symbol I have not seen before. It's shown here between 3 - Output and 2 - ...
- 1,181
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Why was so much TTL logic design "negative true"?
I've been spending time with schematics debugging busted 1970s TTL-based computing circuits. I'm sure this is a more general question but I'll ask it in this context since that's what I'm exposed to.
...
- 2,131
17
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2
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How does TTL serial work?
I've been trying to find a good description of the TTL serial "standard" without much luck. I understand that serial transmit (TX) and receive (RX) lines idle high (at VCC) and that they drop to ...
- 2,554
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What logic family is best for general-purpose hobbyist stuff?
I need to buy a few logic ICs. Which family should I get? HC? HCT? Which kind is best to have lying around in a parts box, for maximum compatibility with unpredictable future projects? Wide supply ...
- 28.8k
13
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How is this circuit for level converting (5V<>3.3V) working?
Does anybody know, how is this circuit exactly working? It is level converter between 5V and 3.3V logic and it is bi-directional.
I have some theory, but I am not sure with it (I never worked with ...
- 957
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4
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When is it appropriate to mix 74LSxx components with original TTL 74xx?
I spend almost all my tinkering time with 1970s era logic circuits, which use almost all original 7400-series TTL. I do a fair bit of repair and am now starting to design additional logic to work with ...
- 2,131
11
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4
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Should I use CMOS vs. TTL?
Now, I know that this question has been asked so many times that it seems like I'm trolling, but I must point out that I couldn't find the right answer to this question anywhere.
So yeah, CMOS and ...
- 1,937
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Does this circuit have marginal voltage level problem?
As a research for the problem I described here I found this circuit by Maxim:
This is clock doubler, and must be a really good fit in my case as input frequency is very well defined.
However looking ...
- 7,120
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Buffering a Digital Microcontroller Signal for Connecting to an Optocoupler
I frequently work on projects in which I use optocouplers for isolating digital +5VDC control signals (for example, from a microcontroller) from the rest of the circuit. However, since these work by ...
- 747
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1
answer
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How to convert a digital signal from 24V to 5V
I have an industrial automaton that gives me a digital signal (24V or 0V) on its outputs and I want this signal to control an integrated circuit, but the integrated circuit only takes a TTL signal in ...
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How to manufacture chip on board?
I am a developer of a cheap product and i have no experience in mass production. Device is fully functional and represents a single sided PCB, a microcontroller, a bunch of diodes and a few passive ...
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Rising edge pulse detector from logic gates
The circuits I describe are entirely made of 7400 series logic gates (7402, 7404 and 7408 ic).
I'm trying to build a rising (positive) edge pulse detector using logic gates.
The following circuit ...
- 309
9
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6
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Multiplexing UART
I'd like to interface my main microcontroller's hardware serial port to more than one device at the same time. My understanding is that UART on my microcontrollers is based on an active-low 5V TTL.
(...
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