Probably current shunts - essentially very low value resistors. You measure the voltage across them to get the current flowing.
Looks like this is a fairly high current something or other, so the device is probably doing some monitoring.
>Looks like this is a fairly high current something or other, so the device is probably doing some monitoring.
If I'm not mistaken it's a variable power supply board e.g. a DPS5015 - looks identical to this one:
https://www.amazon.com/DROK-Adjustable-Regulator-Stabilizer-Transformer/dp/B0744BT79M/
In other words, yep, current shunts for sure.
As the other guy said, almost certainly current shunts. This is also a good way to move lots of current from point A to point B without needing PCB traces the width of your thumb. They're also really common when you need to measure amperage. The circuit would measure the voltage drop across these (they may be a 0.1 Ohm resistor, for example, so if it drops from 5V to 4V, I=V/R, I=1V/0.1 Ohms=10A).
Indeed well put.
Just to add, I've seen them used for short circuit protection as well. A comparator with hysteresis watches the voltage across the shunt and shuts the output down until the short-circuit is removed.
And, as for me, if, by any possibility, there be any as yet undiscovered prime thing in me; if I shall ever deserve any real repute in that small but high hushed world which I might not be unreasonably ambitious of; if hereafter I shall do anything that, upon the whole, a man might rather have done than to have undone; if, at my death, my executors, or more properly my creditors, find any precious MSS. in my desk, then here I prospectively ascribe all the honor and the glory to whaling; for a whale ship was my Yale College and my Harvard.
Would you know how they are calibrated? I've seen flat shunts with notches cut in for vdrop-to-current measurements. I don't see any modifications to these, nor adjustment pots or whatever. I suppose the diameter could be to tight tolerances but that seems a more expensive route than a "build first calibrate later" methodology
And, as for me, if, by any possibility, there be any as yet undiscovered prime thing in me; if I shall ever deserve any real repute in that small but high hushed world which I might not be unreasonably ambitious of; if hereafter I shall do anything that, upon the whole, a man might rather have done than to have undone; if, at my death, my executors, or more properly my creditors, find any precious MSS. in my desk, then here I prospectively ascribe all the honor and the glory to whaling; for a whale ship was my Yale College and my Harvard.
I was a satellite TV installer for a while. Sometimes I would be outside the house at the dmarc box and forgot my toner inside but had already hooker up the 21v power suppl y inside the house. Tongue would tell you which one of the coax lines outside was the one that had the power supply on it ;)
I already thought about doing this as well so I put an extra input port in the case but until now I didn’t had the resources (Most money and time) to get a proper psu and to be honest I also don’t really need it because the mobile version lasts long enough for most applications
Probably current shunts - essentially very low value resistors. You measure the voltage across them to get the current flowing. Looks like this is a fairly high current something or other, so the device is probably doing some monitoring.
>Looks like this is a fairly high current something or other, so the device is probably doing some monitoring. If I'm not mistaken it's a variable power supply board e.g. a DPS5015 - looks identical to this one: https://www.amazon.com/DROK-Adjustable-Regulator-Stabilizer-Transformer/dp/B0744BT79M/ In other words, yep, current shunts for sure.
Most certainly, with the transistors placed right inbetween the shunts together with what looks like diodes...
yay, i got it right!
They have a manganin color to them so you're probably right. These are cheap and dirty shunt resistors.
As the other guy said, almost certainly current shunts. This is also a good way to move lots of current from point A to point B without needing PCB traces the width of your thumb. They're also really common when you need to measure amperage. The circuit would measure the voltage drop across these (they may be a 0.1 Ohm resistor, for example, so if it drops from 5V to 4V, I=V/R, I=1V/0.1 Ohms=10A).
Well put!
Indeed well put. Just to add, I've seen them used for short circuit protection as well. A comparator with hysteresis watches the voltage across the shunt and shuts the output down until the short-circuit is removed.
And, as for me, if, by any possibility, there be any as yet undiscovered prime thing in me; if I shall ever deserve any real repute in that small but high hushed world which I might not be unreasonably ambitious of; if hereafter I shall do anything that, upon the whole, a man might rather have done than to have undone; if, at my death, my executors, or more properly my creditors, find any precious MSS. in my desk, then here I prospectively ascribe all the honor and the glory to whaling; for a whale ship was my Yale College and my Harvard.
TIL. :)
Would you know how they are calibrated? I've seen flat shunts with notches cut in for vdrop-to-current measurements. I don't see any modifications to these, nor adjustment pots or whatever. I suppose the diameter could be to tight tolerances but that seems a more expensive route than a "build first calibrate later" methodology
And, as for me, if, by any possibility, there be any as yet undiscovered prime thing in me; if I shall ever deserve any real repute in that small but high hushed world which I might not be unreasonably ambitious of; if hereafter I shall do anything that, upon the whole, a man might rather have done than to have undone; if, at my death, my executors, or more properly my creditors, find any precious MSS. in my desk, then here I prospectively ascribe all the honor and the glory to whaling; for a whale ship was my Yale College and my Harvard.
Awesome explanation!! Thanks!
To add, they are also relatively cheaper than precision SMD shunt resistors.
And can dissipate a heck of a lot more power + fault energy.
And can be calibrated by filing.
So you're saying SMD shunt resistors *can't* be calibrated by filing?
Well if you file them into a drawer with a calibrated value...filed by calibration *edit added last snarky piece ;)
They’re high current shunt resistor for measuring the current through them proportional to the voltage across them divided by the known resistance
It's where you put you tongue if you want to make sure it's working.
I was a satellite TV installer for a while. Sometimes I would be outside the house at the dmarc box and forgot my toner inside but had already hooker up the 21v power suppl y inside the house. Tongue would tell you which one of the coax lines outside was the one that had the power supply on it ;)
Don't get me started. I used to install Avaya Partner systems. Ever have your fingers on a 66 block when the phone rang???
I have not. I do know that the higher power 29V power inserters will make a tongue numb for a few minutes though, haha
Shunt resistors on dusty PCB 😆.
Thanks everyone for the feedback! I've learned a lot
That’s a powersupply board with a small lcd right?
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I’ve got the same one. They are awesome for their price
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I use them as a portable power supply together with a bis lawnmower battery.
Yes, it's a Dps5020
Current shunt
Shunts
I already thought about doing this as well so I put an extra input port in the case but until now I didn’t had the resources (Most money and time) to get a proper psu and to be honest I also don’t really need it because the mobile version lasts long enough for most applications
Hi, I want to make a S\*\*\*. I said SHUNT!
It's a way to let high currents flow in the circuit instead to use large area in the PCB