Why am i not getting a charged capacitor graph

Thread Starter

tienk

Joined Apr 8, 2024
76
1715860010912.png
Im supposed to get a charging graph taking 10s when it outputs 5V (high0 which it is but for some reason, I'm getting a straight line
 

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Ian0

Joined Aug 7, 2020
10,277
U9 and U11 have switched on simultaneously and SPICE has blown up.
But seriously, what is meant to happen, and where do you hope to observe this charging waveform?
 

Thread Starter

tienk

Joined Apr 8, 2024
76
U9 and U11 have switched on simultaneously and SPICE has blown up.
But seriously, what is meant to happen, and where do you hope to observe this charging waveform?
like I said when the output of the comparator is 5V (high) which it is, C8 is supposed to be charging as it is a rc circuit (10s)
 

crutschow

Joined Mar 14, 2008
34,855
i got this when i changed to 1ms but its supposed to be charging so is it the circuits fault or have i missing anything
Hard to say since I don't understand what that convoluted circuit is supposed to do.
Using rectangular symbols for the active devices, instead of the normal ones for comparators and transistors/MOSFETs makes the circuit very difficult to follow.
Can't help you until you convert those symbols to the correct ones.
 

Thread Starter

tienk

Joined Apr 8, 2024
76
1715880446438.png
for some context, I have been trying to simulate this part of the circuit but for some reason not getting the results needed. Just a quick explanation of this section, when comparator U5 outputs low U11 (Pmosfet) discharges C8 quickly, which I simulated and works fine. However, the part that is not simulating correctly is when the output of comparator U5 is high, U11 (pmosfet) will charge C8 which will take 10s. As for U9 (Nmosfet), it charges C8 quickly when the circuit is powered up, meaning all capacitors are usually discharged before power up. I am posting this because all the results I get are the opposite of what I expect which makes me extremely confused as I am confident the circuit is right, so any help is extremely appreciated
 

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Alec_t

Joined Sep 17, 2013
14,417
C8 can't charge (except initially, via N-FET U9) because P-FET U11 is repeatedly discharging it at 4ms intervals, since V5 over-rides U5. Remove V5.
Perhaps you want R21 (560k) in parallel with C8?
 
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eetech00

Joined Jun 8, 2013
4,056
View attachment 322495
for some context, I have been trying to simulate this part of the circuit but for some reason not getting the results needed. Just a quick explanation of this section, when comparator U5 outputs low U11 (Pmosfet) discharges C8 quickly, which I simulated and works fine. However, the part that is not simulating correctly is when the output of comparator U5 is high, U11 (pmosfet) will charge C8 which will take 10s. As for U9 (Nmosfet), it charges C8 quickly when the circuit is powered up, meaning all capacitors are usually discharged before power up. I am posting this because all the results I get are the opposite of what I expect which makes me extremely confused as I am confident the circuit is right, so any help is extremely appreciated
You'll get more help and better answers if you use standard component symbols to "indicate function" rather than "boxes", in your schematics. If you do, your schematics will be easier to understand.
 

Papabravo

Joined Feb 24, 2006
21,324
The real answer is that you are new to this, don't exactly know what you are doing, lack the skills to figure out what is wrong, and can't get anyone to help because you are taking shortcuts in your symbol creation and schematic entry. A bit harsh -- perhaps, but you might want to take the advice you have gotten so far and just fix things up or go for a simpler example. At least that may be a pathway to better understanding of what is going on.
 

crutschow

Joined Mar 14, 2008
34,855
Since you have made no effort to improve your schematic I will expand on that.
Clean and properly drawn schematics are the language of electronics.
Your schematic is like a bad translation of one foreign language into another.

You don't see to want to make the extra effort to correct the schematic, but want us to make an extra effort to understand it.
 
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Papabravo

Joined Feb 24, 2006
21,324
Since you have made no effort to improve your schematic I will expand on that.
Clean and properly drawn schematics are the language of electronics.
Your schematic is like a bad translation of one foreign language into another.

You don't see to want to make the extra effort to correct the schematic, but want us to make an extra effort to understand it.
And, there are certain things, up with which we will not put.
 

Thread Starter

tienk

Joined Apr 8, 2024
76
The real answer is that you are new to this, don't exactly know what you are doing, lack the skills to figure out what is wrong, and can't get anyone to help because you are taking shortcuts in your symbol creation and schematic entry. A bit harsh -- perhaps, but you might want to take the advice you have gotten so far and just fix things up or go for a simpler example. At least that may be a pathway to better understanding of what is going on.
Yes I am new to this and I'm just trying to find out how to change to standard symbols. So thank you
 
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