Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
563
questions
2
votes
3
answers
2k
views
Which 74xx logic families are overvoltage tolerant on their outputs?
Here's my dilemma: I have a 3.3v active-low logic line, and I want to use it to drive a 5v active-low logic line. The 5v line already has a pullup, so my plan was to use an open-collector buffer IC ...
- 7,749
7
votes
2
answers
7k
views
Interfacing Arduino to C64's tape port
Update: a practical implementation of this is done in the Tapuino project made by Peter Edwards. Check it out, everything is open sourced: https://github.com/sweetlilmre/tapuino
I'm working on a ...
- 179
1
vote
4
answers
975
views
Is it possible to build a inverter that operates at a frequency set by an LC tank using ONLY that LC tank and transistors?
I was always dissatisfied with inverters because it seems like an LC tank and transistors would be all you need. However, after much time spent simulating and a few false positives experimenting, I am ...
- 841
5
votes
1
answer
671
views
Dual power supply confusing TTL serial?
Sorry for the vague title: I'm a bit of a noob at analogue electronics, more a logic &software guy. Basic problem is I'm sitting at the end of a cable with a USB powered Arduino trying to send ...
- 51
2
votes
2
answers
17k
views
Using Arduino UNO as a USB to TTL converter for unbricking a Seagate Barracuda 7200.11 Hard Drive
Is it possible to use an Arduino UNO as a USB to TTL converter for unbricking a Seagate Barracuda 7200.11 Hard Drive
And if it is possible : how to program it?
The Arduino UNO has no FTDI chip.
In ...
- 21
4
votes
2
answers
12k
views
What is the fastest 7400 series family? Is 74VHC faster than 74AHC?
What is the fastest 7400 series logic family?
Is 74VHC* faster than 74AHC*?
This list does not seem to be in any particular order:
http://en.wikipedia.org/wiki/7400_series
- 1,163
3
votes
2
answers
549
views
Why is my XNOR output always low?
I recently bought some Texas Instruments TTL chips. So far they've been OK, except the XNOR (SN74HC266N) chips (I've tried 3, including one that's never been in my "real" circuit) always output low ...
- 289
26
votes
8
answers
13k
views
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
25
votes
8
answers
5k
views
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
1
vote
2
answers
2k
views
Boost Converter for TTL circuits to drive large loads
I've got a small PIC-based TTL circuit device, powered by a 4.5V coin cell, that needs to drive a solenoid which requires 12V. Obviously my logic level device can't directly power that so I could ...
- 334
1
vote
1
answer
4k
views
Creating a one-digit scoreboard using logic circuits
I'm creating a one-digit scoreboard on a breadboard. Naturally, I have a BCD to 7-segment decoder and a 7-segment display. But I don't know how to automatically increment the display. (It's for a game,...
- 113
13
votes
1
answer
4k
views
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
5
votes
3
answers
2k
views
Going from Transistors to Gates to.....IC's?
So I am trying to understand I guess what is probably a basic concept of computers.
I was taking a look at this previous question:
From Transistor to Gates
And it's accompanying link:
http://www.cs....
user3073
4
votes
3
answers
6k
views
PCB and trace design for high-speed TTL
I am designing high-speed TTL-based processor.
I will be using only fast AC, ACT and LVC series, so switching frequencies will be in 100Mhz range with 1-3ns fronts.
I plan to use homemade 2-sided ...
- 3,219
8
votes
3
answers
12k
views
Bidirectional level swiching 5V <-> 3.3V
I am looking to interface a 3.3V device with a 5V one. This will require the shifting of the logic levels between the two devices.
Doing this in one direction is a trivial matter, but I need to do ...
- 56.3k
6
votes
1
answer
3k
views
Should I calculate a resistor value for driving indicator LEDs from TTL outputs?
Traditionally I have always used a \$1\:\mathrm{k\Omega}\$ resistor as a current limiting resistor for driving an LED direct from a TTL (or 5V CMOS) output. I can't remember how I came by this value -...
- 56.3k
2
votes
2
answers
2k
views
Is my SparkFun RS232 Shifter SMD faulty?
Product Link
I am connecting this to an Arduino. (once Arduino programmed I removed the USB connector as it shares the serial comms with Pin0&1)
RS232<->Arduino
VCC <-> 5V
GND <-> GND
...
4
votes
3
answers
2k
views
IC chips and datasheets
I'm still just beginning my adventure into electronics and IC chips and datasheets have me confused so I'm going to ask a series of beginner questions will help me and hopefully others as well.
There ...
- 1,708
0
votes
2
answers
274
views
Three-state inverting octal buffer
I'm looking for a three-state inverting octal buffer for a replacement part for an old microprocessor lab. The package should be DIP. Ucc should be on pin 20. Chip select should be at pins 1 and 19 ...
- 3
14
votes
4
answers
2k
views
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 ...
- 28.9k
17
votes
2
answers
49k
views
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 ...
- 2,564
5
votes
2
answers
2k
views
CMOS (or CMOS compatible) shift register with latched open-drain outputs
I've been looking for a 3.3V compatible shift register (SIPO) with latched open-drain outputs. I've settled on a 74xx596 (not a '595!), but of all the 74xx CMOS series I've been looking at omit this ...
- 31.9k
5
votes
4
answers
6k
views
Switching relay with a PNP and TTL levels
I can not wrap my head around the fact how I can drive a relay (24V, 160ohm) with an tip32a PNP transistor which has TTL inputs from a controller.
I can easily calculate my resistors when I use the ...
- 464