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Questions tagged [ttl]

Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.

1 vote
0 answers
201 views

How to obtain the counting of TTL pulses from an FPGA?

I'm currently working on a project in which I need to program an FPGA in order to connect it to a photon detector, that generates a TTL pulse when detecting a photon; I need to count this pulses, ...
Jorsa's user avatar
  • 11
0 votes
2 answers
73 views

Tie an enable pin to ground when another pin is high

I am designing a simple circuit with two ICs. IC1 has an enable pin that is internally pulled up with a 10Kohm resistor. To disable IC1 you have to tie this pin to ground. IC2 has an serial presence ...
mwp's user avatar
  • 103
1 vote
3 answers
149 views

Converting a 74LS74 and a 74LS193 to CMOS. What inputs need pullups and what needs pulldowns

I have a circuit I traced out off an old, dead PCB that came from the early 90s. It was using TTL chips back then. One thing I noticed is that it has a dual flip-flop. One flip-flop is being used as a ...
Erik Vincent's user avatar
0 votes
2 answers
99 views

Need help identifying circuit diagram symbol

In the datasheet for Hamamatsu s13131-1536 CMOS line sensor(https://www.hamamatsu.com/content/dam/hamamatsu-photonics/sites/documents/99_SALES_LIBRARY/ssd/s13131-1536_kmpd1159e.pdf) there is this ...
Mikhail Seryukov's user avatar
1 vote
3 answers
98 views

Generating TTL-level signal from an analog fast pulsed high-voltage DC signal

I am exploring feasible ways to design a circuit to generate TTL-level digital signal from an analog pulsed DC voltage output. The voltage range of the pulsed DC signal can be from 0 V to 3 kilovolts ...
Allison's user avatar
  • 29
1 vote
2 answers
136 views

Converting a fast-switching 0-2.5V input to TTL signal

Dear fellow engineers, I am attemping to convert a fast switching (~ns) 0V - 2.5V pulse from FPGA into a TTL-standard (0V - 5V) signal. I have been browsing for voltage regulators online. Most of them ...
Boan Fang's user avatar
0 votes
2 answers
80 views

Is it possible to connect ATMEGA328 to type-C and read data without a USB-TTL converter?

there was a task to create the most compact device with atmega328 on board, but the question arose whether it could read data from type-c without a ttl converter ...
Settings's user avatar
  • 129
2 votes
1 answer
188 views

Turn on/off a LED using a D-FF and a transistor

I'm trying to control a LED using some microcontroller and I designed a circuit using a D-FF and a transistor to handle it. It looks like this: So I can control when to turn it on or of by simply ...
sergiopolog's user avatar
6 votes
1 answer
257 views

Active pull-down in LSTTL totem-pole output

The lower totem-pole transistor of a LSTTL IC frequently has an active pull-down from base to emitter (ground). Here is an example from TI's SN74LS93 datasheet. I was curious how this active pull ...
Math Keeps Me Busy's user avatar
0 votes
2 answers
136 views

What is the application of the 74LS373?

Looking at the truth table, the data from the D(n) input are directly transferred to the Q(n) output when the high state appears at the C (CLK) input. If there is a low state, there are no data at the ...
Jerzy Przezdziecki's user avatar
2 votes
2 answers
406 views

3V oscillator to 5V µC with an 74HCT inverter (12.8 MHz) - bad idea?

I'd like to use an AVR (ATmega328P-AU to be precise) in combination with a fairly accurate oscillator for timing purposes. I stumbled upon the fact that oscillators which have greater accuracy mostly ...
Korbinian's user avatar
2 votes
4 answers
474 views

Convert a 0 V / 3.3 V trigger signal into a 0 V / 5V trigger signal (TTL)

I have a device sending a square trigger signal 0V / 3.3V, with a BNC connector. (We usually call it a TTL signal, I don't know if it's the common name? is it relative to Transistor-Transitor-Logic?) ...
Basj's user avatar
  • 1,936
0 votes
1 answer
308 views

MAX3232 ESE+ Not Working but ST3232C and MAX3232 Working on same PCB

I have designed a pcb for Rs232 to TTL, UART converter for using ESP32. I will control an LCD with ESP32. Some IC's (MAX3232 ESE+) heating at the first start. and not working just heating and heating. ...
mehmet's user avatar
  • 1,139
0 votes
6 answers
1k views

Output voltage level of TTL gate

The output voltage level of the TTL logic family is from 0 to 0.4 volts (LOW) or 2.4 to 5 volts (HIGH). Suppose we have a TTL inverter with a square wave of 5 volt amplitude as input (0 volt and 5 ...
MAJID AHMAD's user avatar
0 votes
1 answer
149 views

TTL bus termination physical circuit layout

I'm breadboarding a simple data bus terminator for a 1970s TTL computer bus that was normally unterminated. I'm trying both passive and active termination to see how they work, but have a question on ...
BZo's user avatar
  • 2,131

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