Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
563
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Logic level converter from 29V to 5V schematic
Does it looks a good schematic to do a proper 29 V to 5 V logic level conversion, any improvements or suggestions?
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3
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Connecting a GPS to computer: Jackson Lab LC_XO serial TTL to RS232 port on computer motherboard
I am trying to hook up my Jackson Labs' LC_XO GPS disciplined oscillator (GPSDO) to my computer motherboard COM/serial port so I can talk to it and for it to send back NMEA messages. Basically, I am ...
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How to connect RS232 level shifter?
I'm trying to use this:
https://www.sparkfun.com/products/449
to connect my RPi to my computer via a USB to serial device. (And eventually connect the RPi to other legacy serial devices)
My questions:
...
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SIM800L V2 not responding to AT Commands from Putty over USB-To-TTL PL2303
My SIM800L V2 RoHS (the blue one) although it connects to the network and registers just fine, it's not responding to AT commands sent over the PL2303 (USB-STC-ISP) USB-To-TTL Adapter through which it'...
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Is there a problem with a resistor inline between two TTL gates?
I want to adapt the output of a board to drive additional logic instead of an LED. The driver board has a current limiting resistor before the signal is routed to the connector. Is there any problem ...
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Why am I seeing -5 V or lower on the output pins reading an Intel 1702A EPROM?
I am building a breadboard/Arduino reader to dump the data on a very old Intel 1702A EPROM chip. (data sheet) When doing some basic testing by tying all the address pins to ground, I am seeing ...
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Trigger TTL input signal with a micro switch
I used to have a machine where an action could be triggered on a pontential free contact with a simple micro switch (that worked pretty easy and well for me). That machine got replaced and the new ...
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Convert PWM to TTL signal via IC or circuit
I'm fairly new to TTL logic. I have a PWM output 0-3.3V that I need to convert to a TTL 5V logic as the sensor only accepts a TTL signal.
Is there an IC that would do this or a circuit I can build?
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SN75176 with 3.3V
Can I connect the SN75176 RS485 transceiver with a 3.3V microcontroller? The datasheet says that it must be powered with 5V and all inputs / outputs are TTL, but I'm not sure since the minimum high ...
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Why does the 74LS32N behave like an AND gate?
First of all I am a beginner.
I am practicing with the 74LS32N (OR Gate) IC , I noticed that it behaves like an AND gate instead of an OR Gate.
Only when both the inputs are 1 , the output is 1 , (Led ...
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8-channel/octal equivalent of 74HC125
I have a 12v powered 16-channel relay board, that required 5v logic level signals to control the relays. However, I am using a Raspberry Pi to control this, which has 3.3v logic level outputs. I have ...
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74HC08N doesn't latch [closed]
I am using the 74HC08N chip. Why doesn't the first AND gate latch itself?
I have connected the output of the first AND gate to its own input.
I have used two resistors, the one on top is a pull-up and ...
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0
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What is "level of saturation" for transistors?
This is a term I've never heard of, and it's presented on a work analysis of a ttl nor circuit. It basically says that the transistor that links the output with the ground should have a higher "...
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What is the function of the latch pin on my 74HC595 IC?
I am using this code with a 74HC595 IC to control a 4 digit 7-segment:
...
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How do I step down a 12V pulse width modulation signal to 5V?
I want to control my new laser module from my repurposed 3D printer. The laser module has a 12V pin for power, a ground pin and a 5V PWM pin. My board's fan-control port can generate a 12V PWM signal, ...
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Fan out of TTL Circuit
In this image When calculating the fan out of the TTL circuit
the current in the TTL drive output is 16mA and is divided into the emitters of the load each emitter has 1.6mA because the fan out is 10.
...
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Delay TTL signal from board power supply
To preface, I don't come from an EE background so I'm sorry if this question is extremely simplistic.
I have a shutter controller board that allows me to open and close a shutter (optical iris) with a ...
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"TTL OUT" on PCB
I was wondering what this TTL OUT means and what type of cable it takes.
I think it might take a display or a camera but unsure.
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What are the output logic levels of this STM32?
I am struggling getting my head around the input and output logic levels, mostly the output levels of this STM32 (STM32F446xC/E).
This table shows the output logic levels as dependent on if it is a ...
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Optical pulse sensor not producing a clean TTL pulse
I have two of these optical pulse sensors monitoring LEDs on my electric and solar meters - Optical Pulse Sensor - Github
The first sensor outputs nice TTL pulses at 5V, the second sensor outputs ...
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2
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TTL NOR Gate analysis
I'm looking at the design below. I am reading this webpage where the picture came from.
What I'm aiming at is the wisdom behind the design. Looking at the two transistors facing downward, I assume ...
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74f269 counter getting very hot
Hi I'm a DIY enthusiast and I got stuck with the circuit that I designed.
The counter is getting very hot from the moment It's powered up.
In my setup the 330Ohm resistors at the outputs are ...
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Modbus acquisition timings
Part 1
What is the standard timing method for bits acquisition for a receiver using Modbus RTU?
For example, for UART: "Communicating UARTs have no shared timing system apart from the ...
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Design a relay driver from TTL input with common parts
I would like to drive a pneumatic relay from a TTL GPIO source, the TTL may be 0-3.3v or 0-5v
I would like supply and cut 12v to the relay to control the air.
I have a concept of what i'm trying to do ...
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1
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Is powering the Nuvoton N76E003 with just the UART0 pins legitimate?
I bought an 8 channel USB/UART controlled relay board from banggood.com:
https://www.banggood.com/2-in-1-DC-5V-8Channel-USB-Serial-Port-Relay-Module-UART-RS232-TTL-Switch-Board-CH340-for-Windows-Linux-...
user97497
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What is the methodology behind 555 timer design?
Small circuits in TTL and RTL we could do intuitively, without any methodology. But what about a complex circuit like 555 timer?
If it was designed using logic gates, it could be easily deduced by ...
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Combining CMOS and TTL with drivers and Leds with relay driver
I need some practical advice on how to combine different component types.
I designed a circuit with at the heart an up/down counter (74f269) The outputs of the counter are connect to via 330 ohm ...
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0
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DC>DC Isolated Converter (ADuM5401)
I'm in a bit of a quandary as to if I've approached something the right way or if there's an obvious solution I'm missing.
(Sorry for lack of schematic, still WIP).
Goal:
Self-powered isolated USB >...
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TTL to USB (CP2102)(Driving 5V USB)
I have a USB to TTL Adapter. The Adapter uses the CP2102.
I noticed that the CP2102 seems to derive it's power from the USB V+. My problem is that I need to supply power to the USB. The reason is that ...
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Is there an IC that works like the PL2303 for TTL TO USB? [closed]
Is there an IC that works like the PL2303 for TTL TO USB and can connect to android device with driver?
I have search a lot but I did not find such a thing.
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1
answer
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74LS47/74LS247 BI/RBO-pin usage
I am currently playing around with a 74LS247 BCD to 7 segment decoder. The basic usage for decoding works perfectly fine.
But I would like to test out everything this IC has to offer including the ...
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0
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Connecting RS232 GPS Board to Raspberry Pi
I purchased a NEO-6M GPS board to connect to my Raspberry Pi, and when I bought it I didn't realize that it was meant for RS-232 communication instead of UART TTL (which I believe is what the ...
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CMOS vs TTL power and impedance
I need to compare and contrast a CMOS IC with a TTL IC. I've chosen a quad 2 input NAND gate IC, 7400 for the ttl version and 4011 for the CMOS. I'm having a bit of trouble with 2 of the requirements.
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Switching characteristics in terms of TTL flip flops
I am a complete novice when it comes to electrical things. Fine at digital logic, haven't done electricity since high school.
I'm looking at flip flops and I've run into something called switching ...
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How can I avoid a clock glitch?
I have a clock with a 50% duty cycle, driving a 3-bit ripple counter.
When Q2 is high, external lines such as address are stable. I want to generate a short read pulse between 50% and 75% of the Q2 ...
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Are TTL to USB converters bi-directional? [closed]
I'm trying to convert 5V TTL signals into USB signals that a PC can read. However, most converters that I'm able to find are defined as USB-TTL converters. Can I convert TTL signals to USB signals ...
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0
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TTL in an RF switch
I am hoping to find help on how to properly connect supply voltage to my switch assembly in order to actuate. My switch has input requirement of +15, -15, GND, and +5V. Also, the 5v logic inputs. ...
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How to prevent short circuit between output pins
I am trying to hack some signals coming from an old computer going to a Floppy drive using an ATtiny1614 microcontroller.
Normally the computer has full control of the signal lines but at some window ...
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How to interface a thermal printer to an Arduino
I've a thermal printer which has TTL, RS232 & a four pin interface. I want to connect it to an Arduino and take printouts with it. It has the following pinouts:
RS232 & TTL
GND
TXD
RXD
DSR
...
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2
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325
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Using USB-RS232 adaptor for USB-TTL connection? [closed]
Seems there are plenty of questions relating going in the opposite direction, but I couldn't find anything that really told me if I could do this..
I have one of these https://uk.rs-online.com/web/p/...
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BJT transistor max switching frequency vs FET in high frequency computer architecture
Why arent BJTs used with RISC architectures to produce very high speed relatively sparse CPUs? My understanding is that BJTs don't have the forward bias gate capacitance requirements of FETs which is ...
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Does the 74LS09 have an adequate internal input pullup?
I want to feed an output of the 74LS05 open collector inverter into one of the inputs of the 74LS09 AND gate. The internal schematics in the datasheet shows that there is an internal resistor and 2 ...
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Custom HDMI-to-( TFT or LVDS ) decoder/driver
I am working on a custom-made handheld PCB based around a PI Compute Module 3+ and one of the hardest steps I have found is how to include an HDMI-to-50pin-TTL driver on my PCB to run an LCD TFT 7&...
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1
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TTL to 232 with no conversion?
I was reading a blog about someone's application to ingest a TTL signal to a device and got perplexed.
The author connects what appears to be a 3.3V TTL signal directly to a RS232 port (and it ...
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Bi-colour LED resistor value
I am trying to calculate a suitable resistor to give about 2mA to the a bi-colour LED in the following configuration:
simulate this circuit – Schematic created using CircuitLab
The LED package ...
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1
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Convert 24 V signal to 5 V with galvanic isolation
I need to make an acquisition card signal (24 V) conversion to TTL signals (5 V) usable by intelligent cards with galvanic isolation.
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2
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Can Bruce Abbott's inverting TTL to +/- 12V level shifter be improved to better frequency response and better matched impedance?
I am working with Bruce Abbott's awesome level shifter here.
Level transformation 0/+5 V TTL logic to +/-9V how to maximize gain and frequency range (DC to 4 MHz)
simulate this circuit – ...
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TTL Gates Power Dissipation Values
I am not finding any datasheets that provide clear information about the power dissipation of some gates of the 74LS series:
08, 02, 04, 00, 32 and 86.
Can someone help?
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How do I build an RC-base negative edge detector, that makes a low pulse on a falling edge?
I keep coming back here searching for an RC-based negative edge detector for TTL levels, that generates a negative pulse on a falling edge. The only place I find this solution is a certain spot in a ...
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Input impedance of TTL driver in a RF switch
I have a RF switch "ZYSW-2-50DR+" which has a built-in TTL driver. So far as I understand, the driver is like a buffer which amplifies the current while keeping the voltage same(unity gain). ...
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