|
Hello, I have a relay based circuit as shown in the photo below and the full schematics is in the attached document ff3.
The circuits based on PC375 relay, how does it work?
Why they need all of those diodes and resistors?
There is no spice model so i am having trouble to know if this acctually will work.
is there some spice model for this relay i could try to simulate the relay circuit?
https://pickercomponents.com/pdf/Relays/PC375.pdf
https://groups.io/g/LTspice/files/Temp/john23/fff3.pdf
https://groups.io/g/LTspice/photo/294510/3804313?p=Created%2C%2C%2C20%2C2%2C0%2C0
|
That schematic is for a particular
application. Forget it. Unless you want to look at how the relay
coil current varies during switching, you can replace the relay
by a voltage-controlled switch. If you need both the SPST and
SPDT functions, that needs a bit more circuitry, using three
voltage-controlled switches., all driven by the same control
voltage If you do need to look at coil current, there is no
point in simulating it, because to get the data to make the
.ASC, you would have to measure how the current varies.
On 2024-07-11 10:59, john23 wrote:
Hello, I have a relay based circuit as shown in
the photo below and the full schematics is in the attached
document ff3.
The circuits based on PC375 relay, how does it
work?
Why they need all of those diodes and resistors?
There is no spice model so i am having trouble to
know if this acctually will work.
is there some spice model for this relay i could try to simulate
the relay circuit?
https://pickercomponents.com/pdf/Relays/PC375.pdf
https://groups.io/g/LTspice/files/Temp/john23/fff3.pdf
https://groups.io/g/LTspice/photo/294510/3804313?p=Created%2C%2C%2C20%2C2%2C0%2C0
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
On Thu, Jul 11, 2024 at 01:23 PM, John Woodgate wrote:
s a bit more circuitry, usin
How this PC375 component works?
I cant see the functionality of the legs in the data sheet.
https://pickercomponents.com/pdf/Relays/PC375.pdf
|
On 11/07/2024 11:59, john23 wrote:
Hello, I have a relay based circuit as shown in
the photo below and the full schematics is in the attached
document ff3.
The circuits based on PC375 relay, how does it
work?
Why they need all of those diodes and resistors?
There is no spice model so i am having trouble to
know if this acctually will work.
is there some spice model for this relay i could try to simulate
the relay circuit?
https://pickercomponents.com/pdf/Relays/PC375.pdf
https://groups.io/g/LTspice/files/Temp/john23/fff3.pdf
https://groups.io/g/LTspice/photo/294510/3804313?p=Created%2C%2C%2C20%2C2%2C0%2C0
What exactly do you want to simulate? Relays are deceptively
complicated. They are nothing like an ideal switch in many respects.
As far as "all of those diodes and resistors" are concerned, most of
them have nothing to with the relay itself. What I can't actually
see in your picture is the current limiting resistor for the relay
coil, or the actual supply voltage for it.
Relay coils normally require a series resistor to limit the current.
They also usually have an parallel diode, because when the
transistor that drives the coil suddenly switches off a large spike
is generated on the transistor side of the coil: V=-dI/dT. A single
diode isn't always the best solution to that, but it is the
simplest. without the diode, the breakdown voltage of the transistor
will likely be exceeded by the spike and the energy stored in the
coil may be enough to blow the transistor up. On the other hand, the
simple diode solution slows down the turn-off. A better solution is
to use a diode, a Zener and a small resistor, but this isn't so
well-known.
For the switched contacts, well...
For a start, there is a delay before the contacts start to move,
because the current in the coil rises linearly depending on dI=V/dT,
and it takes a minimum current to move the contacts against the
spring pressure holding them open (or closed, depending on whether
they are normally open or normally closed - NO or NC). There is
another delay while the moving contact traverses the gap. Then when
it reaches the other contact, it most likely bounces off it a few
times, before settling in its final position. Depending on the
mechanics of the relay, it could take as much as 10ms to switch
between states. This is 1000s of times slower than a transistor
switch.
It is possible to simulate all these effects, but is it necessary?
Only you can answer that, because it depends on what you want to
know.
--
Regards,
Tony
|
As shown on page 4 of the .PDF, the part comes
in eight versions. In all versions, the coil terminals are on
the left. The terminals on the right are for the switching
contacts, and the function of each terminal should be obvious.
On 2024-07-11 11:32, john23 wrote:
On Thu, Jul 11, 2024 at 01:23 PM, John Woodgate wrote:
s a bit more circuitry, usin
How this PC375 component works?
I cant see the functionality of the legs in the data sheet.
https://pickercomponents.com/pdf/Relays/PC375.pdf
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
It looks like there is more than one relay in that schematic. One is LS1 (pc375-2c-12s4-x) and the other is LS2 (V23105A5476A201).
Many relays need no external limiting resistor because they are designed for a particular operating voltage for the coil. I think that is true of these (12 V).
What is the reason for the marked sections (green boxes) in the Photo? Are they not related?
re: "How this PC375 component works?"
When the relay coil is "energized", by having sufficient voltage (12 V) across its relay coil, the switching contacts toggle from the normally relaxed state to the other state. Just like a physical switch does. That is the simple explanation, and that might be everything you need to know about it. At the fine level, there is stuff like the DC resistance and inductance of the relay coil, the currents and voltages needed to pull-in and release the relay, the contact resistance of the switched contacts, the time it takes, contact bounce, etc. etc. All of that might be considered details that someone needs to worry about, but they can usually be ignored to understand "what the relay does". At the end of the day, it's a switch, plain and simple.
On a schematic, the coil and contacts might be drawn separately (as they are for LS1), or as just a "black box" rectangle (as they are for LS2). In the LS1 version on this schematic, you can see that it has DPDT contacts, meaning that it contains two sets of contacts and each one toggles between one pin and another pin. Most likely, pin 5 connects to pin 4 when the relay is not energized, and pin 5 releases from pin 4 and connects to pin 6 when it is energized by Q6. You can "see" that because the relay's coil pulls the armature towards it when the coil has sufficient current. They are usually drawn in the non-activated position, with the armature away from the coil.
Is this what you are asking about?
The PC375 shown in the datasheet comes in multiple versions, with various coil voltages, and various contact arrangements. The diagrams on page 4 of that datasheet show how each one "works". The coil is the small rectangle on the left inside each outer rectangle, so one would apply the appropriate voltage across those two pins to activate ("close") the relay. The relay contacts are towards the right. In those diagrams, the armature (the part that moves) is shown by the line(s) at an angle. They are probably shown in the not-activated condition. Therefore, in Version 1, it is a simple SPST switch, and the contacts are normally open but they close when the relay is energized.
Modeling a relay, how it actually works dynamically, is very challenging in SPICE. I don't know if you have any interest in doing that, or if your question was not SPICE-related. Hopefully you don't need to model the relay in SPICE.
Andy
|
John wrote, "... and the function of each terminal should be obvious."
They are obvious, to anyone who has seen relays before. But I am guessing that john23 has never seen a relay in a schematic before so this is all brand new to him. Once you've seen it and know what it means, you'll never forget it.
The thing to know is that the armature (the part inside the relay that moves) is indicated by the line segment drawn at a 45 degree angle, and it is shown in its released (not activated) state.
Some relay diagrams don't use the method of drawing the armature at an angle, but then you can usually figure it out. In the photo and PDF file you uploaded, the armature is drawn horizontally, not at an angle, but the fat arrows above and below it make it pretty clear that they are the contacts that the armature switches between, and the dotted line means the two armatures are physically ganged (connected together).
Some relay diagrams use terms like N.O. (or NO) and N.C. (NC) to label the contacts. NO means Normally Open and is a contact that is not connected to the armature until the relay activates. NC means Normally Closed. Physical switches use those terms too. The contact with neither NO or NC labels would be the armature.
Andy
|
Hello,suppose we take Version 1, 1C, 3.5mm Terminal Spacing as shown in the photo below.
I dont understand , we have on left side two ports with resistor between them and on the other side we have three ports where there is a connection between two of them.
how the effect side linked to the right side?
what causes that switching of the pin from left to right?
https://groups.io/g/LTspice/photo/294510/3804316?p=Created%2C%2C%2C20%2C2%2C0%2C0
|
john23 wrote, "I dont understand , we have on left side two ports with resistor between them".
That is NOT a resistor. The thing that looks like a resistor (outside of the USA which prefers the zig-zag lines) is actually the relay's coil.
re: "and on the other side we have three ports where there is a connection between two of them."
[ERROR! I made a mistake here. See the next Reply after this one.] I don't know what you mean by "three ports", but it shows two contacts (the circles) and a few lines.
The angled line is the armature, which moves between pointing up-left (as it is drawn), and pointing up-right (which is not shown). The up-left orientation is when the coil has no voltage or current. The up-right orientation closes those two contacts.
re: "how the effect side linked to the right side?"
By magnetism. All relays use magnetism. It is usually not drawn in any way.
In this case, the magnetism pulls that armature from the left to the right. Yes, in the actual relay it pulls part of the armature "towards" the coil, but that is not what it's showing in that figure.
Andy
|
Sorry, my mistake! I was looking at the wrong figure in my last reply. What I wrote was for the top left diagram, "Version 1, 1A".
For the form "1C" version, there are 3 ports (3 pins). The armature (bottom pin) connects "normally" to the left one when the relay is not energized, and switches to the right one when energized.
In THAT diagram, the armature moves towards the right when energized. By magnetics.
Andy
|
Perhaps it’s best to just point the OP to the wikipedia page on relays. Their article explains how relays work and shows the equivalence of the standard relay contact terms (Form A, Form C, etc) and the standard switch contact terms (SPST, SPDT, etc).
|
|
|
Hello,
I will upload a zipped file "Relay-circuit.asc" as an example. The component is a generalized one, but some component values can be edited in the SpiceLine(s)
---
Udo
|
john23 wrote, "I cant see in the attached datasheet bellow the pins in the schematics which are responsible for flipping the switches?"
Where is the datasheet? Do you mean the one for PC375.pdf? You had a worthless link to a digikey.co.uk webpage which does not work (it just loops forever trying to prove that they are robots and I am not one).
In every relay, the pins responsible for flipping the switches, are the pins for the relay coil. In the PC375, they are the two pins going to the rectangle that looks to you like a resistor (but it's not a resistor).
In the latest Photo that you uploaded (33.png), they are pins 1 and 12. You can very clearly see that those two pins go to the coil, which is the rectangular thing with a coil of wire wrapped around it, situated below the relay switch contacts.
With DIP (dual in-line package) parts, such as the PC375, it is common to number the pins starting at one corner, and continuing all the way around the package, counter-clockwise when seen from above (clockwise as seen from below). Missing pins are counted too, not skipped. If it is a 12-pin DIP arrangement, then pins 1 and 12 would be near one another, at one end of the package. For the PC375, there is no pin 2.
I don't want to suggest that the pins are ALWAYS numbered this exact way. The manufacturer might choose to number their pins a different way, and someone else (Varshavsky Yefim ?) who uses the part and draws schematics of safeguard circuits with it might number them another way. It's not a good idea to do that, but it is possible. I am just wondering where you see anything that references pins 1 and 2, because I do not see anything that refers to pin 2, except for your question.
Andy
|
|
|
john23,
Do you have any other engineers near you? Do you work with other engineers? Are you a student and are there other students who know anything about electricity and electronics?
So far, every question in this thread has nothing to do with LTspice or SPICE or simulations. You seem to be having trouble understanding electrical schematics, and that is something that does not belong here in this forum. I am suggesting that these questions are SO FAR off-topic that they should not continue here. Perhaps we could hold your hand through this and in a couple of days we can teach you enough so you can understand what an engineer needs 30 seconds to see without help. But that is not what this group is for. Especially because it isn't likely you will ever need to simulate that relay in that circuit. From what I see, it just switches power on and off. Nothing more. That doesn't need to be simulated. All the stuff around the relay, it can be simulated; but the action that the relay itself does probably does not benefit from being simulated.
Andy
|
john23 wrote, "However The key for switching Q6 is the v23105A5476A201 shown in the photo below."
I don't think so.
The V23105A5476A201 is another relay. I think it switches the +12V supply, which is then applied to the top of LS1.
The key to switching Q6 is everything that connects to its Gate pin. If you follow that part of the circuit backwards, you should be able to figure out what makes Q6 switch.
re: "In what case leg 4 of v23105A5476A201will be with voltage so Q6 opens?"
You can study the schematic and the datasheets and figure it out for yourself. But if LS2 is a relay, then the voltage on pin 4 is either +12 V, or disconnected and around 0 V. And it is probably the same voltage whether Q6 is on or off.
LS2 switches its pin 4 between pin 6 and pin 8. Pin 6 = the net named "rl2" "r12", which has a NC (normally closed) switch to "12v" which is probably +12 Volts. By the way it looks like that switch is meant to be a pushbutton switch. While pushed and held, it breaks that connection to 12v.
Andy
|
john23,
Please, do not upload large video files here.
You need to know what goes to every connector. Having only half the circuit does not help. You need the full circuit.
The datasheet for the second relay has its schematic on it too. I saw that you scrolled right past it! It was near the bottom right of page 2 of its datasheet. It tells you everything about how that part functions and what it does.
Andy
|
Hello Andy , regarding this LS1 relay pin 1 ,16 .
These are the pins which open and close the relay.
The voltage to these pins comes from J27 and J29.
What do you think the voltages the J27 and J29 so it will function properly?
Thanks.
https://groups.io/g/LTspice/photo/294510/3804750?p=Created%2C%2C%2C20%2C2%2C0%2C0
|
john23 wrote, "regarding this LS1 relay pin 1 ,16 ."
I guess you mean LS2. LS1 does not have a pin 16.
re: "What do you think the voltages the J27 and J29 so it will function properly?"
I don't want to guess what it might be. You need to KNOW what the voltages are. You need to KNOW what plugs into those jacks. Guessing is a bad idea and will likely cause errors. This is why I wrote before that "You need to know what goes to every connector. Having only half the circuit does not help. You need the full circuit."
It LOOKS like J27 could be for an LED because the word "LED" is next to it, and if so, it is relatively inconsequential. There is +12 V and a current limiting resistor going to one terminal. So if I were to make an educated guess, the wire that goes to J27 pin 1 probably gets switched to ground, by something somewhere. When it is grounded, the LED turns on. When it is not grounded, the LED turns off. It would probably not be driven by a voltage, it would just be connected to ground or not connected to ground. But that's another guess.
Study the schematic. If J27 has an LED, where does the LED's current path go? Follow the path the current must take. Current needs to go somewhere.
Now consider the relay, LS2. What are pins 1 and 16? You can get that from its datasheet. What voltage does that relay want to have on its relay coil, in order to be activated?
Knowing absolutely nothing about what goes into J29, here is my wild guess about it. It probably makes a connection between its two pins. So, perhaps it is just a switch that plugs into that jack. Like all switches, it either makes contact, or it makes no contact. It does not drive any voltage into J29, it is passive.
This is dangerous without you knowing what actually goes into J29. But you can take it from there and figure out what the LIKELY current paths are and how it functions. Most relays simply get turned on and off, so either the rated voltage or current is applied to them, or it is not applied to them. They usually have no middle-ground, never anything but zero and the normal voltage or current.
Andy
|
John Woodgate
Tony Casey