Hi everyone. I'm trying to design a circuit to measure whether the power sequence is coming from the carrier circuit, but I'm not exactly sure how to do it. Could you help me? Thank you.

 

Imagine if every thread had the subject title “Help me please”.

 

carrier circuit,

What? Your heating circuit not working? or?

 

Hi everyone. I'm trying to design a circuit to measure whether the power sequence is coming from the carrier circuit, but I'm not exactly sure how to do it. Could you help me? Thank you.

What power sequence?

What carrier circuit?

Coming from the carrier circuit as opposed to what?

We aren't mind readers and our crystal balls are notoriously unreliable.

 

Hi everyone. I'm trying to design a circuit to measure whether the power sequence is coming from the carrier circuit, but I'm not exactly sure how to do it. Could you help me? Thank you.

Hi,

Sorry to say but that is the most incomplete question I may have ever heard

You need to be much more explicit when asking a technical question, and if you are going to ask about a comparison you really have to mention what is being compared. You are asking whether one thing is doing something, but it sounds like you should be mentioning the alternative as well. Compare these sentences:
"I'd like to know whether he drove a car on Saturday".
"I'd like to know whether he drove a car or a truck on Saturday".
"I'd like to know whether he drove a car, a truck, or a tractor on Saturday".
and also compare the first to:
"I'd like to know if he drove a car on Saturday".

Your intent sounds like you might either see the "power sequence" coming from one place or another place (two different places) but you don't mention at least one more palce it might come from.
You also provide no info about what the "power sequence" might be, or what the "carrier circuit" happens to look like.

In many cases you have to draw a schematic too so everyone can understand EXACTLY what circiut(s) you are talking about.

Try asking again.

 

Hello, I'm trying to run a D-type flip-flop simulation using the pre-built model in LTspice, but I can't see the output (Q) waveform—or rather, there's no voltage at the output. Is this an issue related to the “Preset” and “Clear” functions, or is it due to a gap in my knowledge?

 

Hello, I'm trying to run a D-type flip-flop simulation using the pre-built model in LTspice, but I can't see the output (Q) waveform—or rather, there's no voltage at the output. Is this an issue related to the “Preset” and “Clear” functions, or is it due to a gap in my knowledge?

What do you mean by "no voltage"? Specify voltages, e.g., 0 V or 5 V, or use logic LOW or logic HIGH.

R1 and R2 are too low in value. You don't need resistors on the output to see a voltage at the outputs Q and /Q.
Omit R1 and R2.

Since /Q is Q inverted, is one 5 V and the other 0 V?

You have 5 V on both PRE and CLR. That is a no-no. The two are trying to set and clear the flip-flop at the same time.
Connect PRE and CLR to GND.

For testing, you don't need a pulse on the D input. Use a logic level, LOW (0 V) or HIGH (5 V).

Your problem is a gap in your knowledge.

 

What do you mean by "no voltage"? Specify voltages, e.g., 0 V or 5 V, or use logic LOW or logic HIGH.

R1 and R2 are too low in value. You don't need resistors on the output to see a voltage at the outputs Q and /Q.
Omit R1 and R2.

Since /Q is Q inverted, is one 5 V and the other 0 V?

You have 5 V on both PRE and CLR. That is a no-no. The two are trying to set and clear the flip-flop at the same time.
Connect PRE and CLR to GND.

For testing, you don't need a pulse on the D input. Use a logic level, LOW (0 V) or HIGH (5 V).

Your problem is a gap in your knowledge.

"no voltage" it means 0V (low)
''You don't need resistors on the output to see a voltage at the outputs Q and /Q.
Omit R1 and R2''. So, is there any other way I can see it?

 

Hello, I'm trying to run a D-type flip-flop simulation using the pre-built model in LTspice, but I can't see the output (Q) waveform—or rather, there's no voltage at the output. Is this an issue related to the “Preset” and “Clear” functions, or is it due to a gap in my knowledge? View attachment 372168View attachment 372165

Your plot shows the voltages on nodes (n004, n002, and n003).

How are WE supposed to know which nodes those are? As I said before, we are NOT mind readers!

Label the nodes in your schematic that you are going to plot. Or, at the very least, describe in words which signals are being displayed in your plot. But labeling them is SO easy, just do that.

Also, when asking for help about an LTSpice simulation, it helps if you attach your .asc file so that others can download it and run it. Posting your files not only saves the people trying to help you time and effort, but it also means that we are actually working with the same file that is causing you problems. Sometimes (but not in this case), the problem is subtle and is not apparent from what is visible on the schematic.

As for your circuit, what do you expect the flip flop to do if you assert the PRE input? What do you expect it to do if you assert the CLR input? What do you expect it to do if you assert both PRE and CLR at the same time?

You don't need R1 and R2 on the outputs. But, if you are going to put them there, use reasonable values. Depending on the device model, it may or may not make a difference to the simulator, but if you put a 15 Ω resistor on a physical logic part that is trying to output 5 V, you are asking it to deliver 333 mA of current, which is more than an order of magnitude more than most logic gates can produce (for some parts, it's closer to two orders of magnitude).

 

"no voltage" it means 0V (low)
''You don't need resistors on the output to see a voltage at the outputs Q and /Q.
Omit R1 and R2''. So, is there any other way I can see it?

Get out of the habit of describing 0 V as "no voltage". It's very incorrect terminology and will lead you into making conceptual errors. It's better to either state the voltage, or describe it using the terms "HI" and "LO" or some equivalent.

To see the voltage on a part pin, just use the part reference designator and pin name, which you can select from the same window that you use to add traces to the plot.

A better way is to put a short wire extending from the pin and assign a label to it.

 

Start by keeping it simple....