Very nice. To minimize the fan noise, put a gap between the heat sink and the fans. You can then shroud it to prevent the flow escaping out of the sides. The noise is actually the fan blades chopping the air on the heat sink fins. Anything more than 5mm should do the trick. I think you will be pleased by the result.
@digitalradiohacker3 жыл бұрын
For those who want a bit of fun, there is DC. For those who want a challenge, there is AC. Need more problems in your life? Increase the frequency. Still not difficult enough? Turn up the wick right into the RF domain. Still falling asleep? Try aerodynamics.
@SebastianScholle3 жыл бұрын
Those mosfets are serious! Some of the priciest one's I've seen used in a diy application, but they seem to be rated correctly for this purpose. Good component selection, I learned something new today!
@TheDanyschannel5 жыл бұрын
Nice video! Used your circuit with smaller transistors with great results! Thanks for sharing!
@KerryWongBlog5 жыл бұрын
You are welcome!
@cryscrystiii70232 жыл бұрын
Please try with FDL100N50F soldered/tinned on cooper sheet (thickness>3mm and surface>25cm2) before radiator mounting. I easily dissipate 600W for a long time with only one MOSFET for a maximum temperature near the capsule of 70C mount on 5Kg aluminum with Sanyo 9SG1212P1G03 120mm/50W.
@OneBiOzZ7 жыл бұрын
Very nice, i have been meaning to make such a load to go along with my other loads for testing, its nice to know some good tested linear mosfets for the task personally i would have amplified the shunts anyway to prevent noise pickup on the input voltage or take it a step further and amplify the shunts for 100mV per amp, use a 10 turn pot and a voltage reference like a REF5010 with a panel voltmeter to monitor the current on the device while being contained and avoiding the use of a microcontroller but its a long term project in my mind also the temperature control is a nice touch!
@KerryWongBlog7 жыл бұрын
Thanks Alyx. Yes, when I get a chance, I probably will make it MCU controlled so I don't have to rely on the voltage standard.
@grerlab27774 жыл бұрын
I tried with a water-cooling system and I was able to get 100A ... Thank you...
@symik37 жыл бұрын
Excellent job, what a good morning to wake up to this :D
@KerryWongBlog7 жыл бұрын
Thanks!
@johnconrad54876 жыл бұрын
Hello Kerry, Remember I said that I had trouble getting down to a low input voltage? These are the test results of my Electronic load. I am working on the design, still a long way to go. i need to find a way to control the current over the full range of input from Vin = 60 V down to Vin = 1 V and 20 Amps down to 0.5 Amp (that's my spec for this) Vmax Vmax Vmin Vmin Vin 60 60 1 1 Iin 19.412 0.736 22.36 20.3 Pin 1164.72 44.16 22.36 20.3 Vinmax = 60 Volts the max input current is 19.4 (approx 20) Amps; and min is 0.736 (0.75) Amps; with 1 Volt input the max input current is 22.36 and min is 20.3 Amps.
@KerryWongBlog6 жыл бұрын
If I read it correctly you were saying that when the input voltage goes down to 1V you could not control the current any more? If that's the case I'd take a look a look at the opamp output as it looks like it's still somehow driving the MOSFET?
@johnconrad54876 жыл бұрын
yeah. it is. i need much better control on this animal. i am still having trouble with it. buuuuttttt.... still persevering... LOL
@cipher-12 ай бұрын
Did you find solution at low voltage? I am trying to do similar this E Load and use another Opams and at low voltage the Gate voltaje is around 12 volts but current is less than when I apply 5 volts.... for example with 5 volts is 12 ampere and with 2 or 1 volts the current go down to half
@richardnanis6 жыл бұрын
Very interesting project! Did you do an accuracy test of shunts? It would be nice to have a display showing the actual amps, voltage (wattage, temperature e.g.) and it also would be nice to set these values to a predefined value. Also setting the resistance would be interesting. You would probably need a kind of Microcontroller/Arduino to do so - but that would be much more useful in my opinion. Also a possibility to log the values to some memory would be useful. O.k. i know - this would make the project much more complicate and i like also to keep it simple :-) One point i dont like too much in this built are these multi-flying cables and these cheap clamps for 100A - this is a weak point i would say. I prefer beefy copper cables and big copper connections that could be easily made by ordinary copper tubing (6mm, 8mm, 10mm, 12mm) with a drilled hole and a screw it gives you very good contact :-)
@Graham19045 жыл бұрын
Very and well done but if it were me, at least for the testing phase, I would have put an Arduino or PIC driven LCD display measuring the mV across both sides of the load and display it as amps. You could of course choose a 4-line display and indicate FET temperatures as well. Nice permanent feature as well....
@SatyajitRoy20487 жыл бұрын
Awesome testing. It would be nice of you if you could plan for a detailed tear down of that HP power supply. It should be fun and informative.
@KerryWongBlog7 жыл бұрын
I doubt it is much different than other switching PSUs though.
@stevebliss60565 жыл бұрын
The IPW60R045CP also has great SOA, and can be used up to 400V at 1A
@davestech63577 жыл бұрын
I have built similar loads like this and have a arc lamp driver very similar. I really cringed when you touched the heat sink of the power supply. Many supplies have voltage on the heatsinks that can kick you or worse. Excellent idea of using the shunts instead of a resistor feedback setup.
@KerryWongBlog7 жыл бұрын
I should have mentioned that I did check before hand that the heatsink of the open frame supply is isolated. But yes, in general you should not touch the heatsink of a live switching mode PS without checking.
@johncoops6897 Жыл бұрын
Just a comment on an old post.... a Current Shunt *IS* a resistor. They are exactly the same thing.
@ATauheed3 жыл бұрын
Can you explain how are you connecting the two grounds (control voltage and PSU). From the looks of it, two grounds are connected together. Wouldn't that mess up the isolation and ground reference and evidently result in the opamps and the MOSFET not working properly. I am a little confused on that part. Can you please explain because I was looking around to make a DIY E-load for a school project where we need to test a fuse that is expected to blow at 75-80 amps and your tutorial is exactly what we need. thank you!!!
@jwong197 жыл бұрын
Very nice approach.
@meirmark7787 жыл бұрын
good work, check the feedback from the shunt to the gate of the mosfet with a scop, myb your circuit is oscillating .( the sound of the first power supply you tested.
@KerryWongBlog7 жыл бұрын
Thanks. I'll take a look when I get a chance.
@Shubham-po2tp3 жыл бұрын
@@KerryWongBlog Please tell me any channel who teaches Electronics from basic using practical s For m resistance to opamp and big circuit I am beginner
@eligijuspranskunas350910 ай бұрын
i made with one transistor, for some reason burns R2 (resistor to the gate)
@Kaxlon5 жыл бұрын
Back in the days before Class D were available for audio we often heard parts "sing" when we pressured the audio amp to the max. =) Great video!
@MinecraftPianoPlayz4 жыл бұрын
Awesome, very interested in this type of thing. Great work!
@markkennard694 ай бұрын
I have a large battery bank constructed from 18650 cells. I wish to present a 50A load when the cells go above 4.2v. Im good with the controls but want to know if mosfets are usable for the load at this low voltage. Primary use is for balancing a string of series cells for 12.6 or 25.2v . Currently I switch in wire wound resistors but the heat that's generated limits me to about 15A. Comments anyone ?
@royrogers7644 Жыл бұрын
How about making a audio amplifier out of it?
@oswaldocunha9455 Жыл бұрын
Nice job. Congratulation !
@gerliansilvasilva8084 Жыл бұрын
Hello Kerry, I am wanting to build an adjustable electronic load capable of draining up to 250 Amperes, I initially build one using 32 IRFP260N mosfets but I believe they will not support for a long time, I am using 4 LM324 comparator based control module doing gate control of the mosfets, As a Shunt resistor each mosfet has a 0.10r 5W resistor, My question is, Is it possible to use 8 mosfets IXTK82N25P to obtain a good current drain? Each control module controls 4 mosfets and would it be necessary to change each Shunt resistor of 0.10r for a smaller value, for example, 0.05r? Would it be necessary to do this or would I have much more efficiency just changing the IRFP260N mosfets for the IXTK82N25P linear mosfets?
@yaghiyahbrenner89027 жыл бұрын
The challenge with electronic loads are the small signal stuff with 0.1% accuracy specs I am busy with one and its bloody tough ,its mostly the tempco and analog section that's the hard part with the various signaling paths depending on the range.
@KerryWongBlog7 жыл бұрын
Indeed, in your case low tempco 4-wire sense resistor and low offset low drift R-R opamps would be a must.
@ovalwingnut2 жыл бұрын
I like the way you think. GR8T infotainment. Thank you.
@JaswanthiMukkamala Жыл бұрын
what is the Aluminium heat sink blocks measurements to withstand for 1kw heat dissipating ?
@bitelaserkhalif Жыл бұрын
Ideal for psu testers
@user-uy4ty9vt2x2 жыл бұрын
I also want to make a 1kw electronic load but I don't know the proper heat sink, where could I get that heat sink?
@Yorumcu639 ай бұрын
Great video
@thecombatengineer70695 жыл бұрын
I watched this a year ago and came back to watch it again. I wonder if you still use this unit? Have you have experimented to ensure the two FETS are sharing the load equally? I bought a Fluke 335 and drive a similar unit based on this design, so MANY THANKS MATE!
@KerryWongBlog5 жыл бұрын
Yes I have been using this load numerous times when testing power supplies and battery banks. The loads are shared pretty evenly by the readings of the shunt resistors.
@jorgeldelapaz69613 жыл бұрын
Great Tutorial. Is the DRAIN (tab) connected to the aluminum Panel, and if its do you insulate it from rest of Project?
@HassanETECH7 жыл бұрын
this is pretty awesome. the only draw back is the bulky size and i know due to high power dissipation. well done 👍 and i subbed to your channel
@KerryWongBlog7 жыл бұрын
Thanks!
@waltschannel7465 Жыл бұрын
I jyst discovered your channel while looking for a circuit for an electronic load. Fantastic job! Where did you get the heavy duty shunts?
@KerryWongBlog Жыл бұрын
Thanks! You can get these shunts on eBay.
@manuelmota92857 жыл бұрын
💡💡💡💡💡 WONDERFUL TEST !!! 💡💡💡💡💡 Congratulations for the excelente work. Thank You for sharing. 👍 Kind regards from Portugal
@KerryWongBlog7 жыл бұрын
Thanks Manuel!
@ourchannel8215 Жыл бұрын
good job...👍👍👍
@zaidhussain52067 жыл бұрын
Really useful project , thank you so much
@KerryWongBlog7 жыл бұрын
You are welcome!
@sheep1ewe7 жыл бұрын
Just found Your channel, lot of great tips and info here, i subbed.
@KerryWongBlog7 жыл бұрын
Thanks!
@SteelBlueVision2 жыл бұрын
So I have a crapload of these critters (IXFZ520N075T2) and am wondering if I should try something similar to what you've built up there. Also, my largest power supply goes up to 200 amps at 12 V (needs to be powered by 240 V, which in the US means combining two 180 degree out of phase outlets into one 240 V)
@ryebis Жыл бұрын
Just came across this, thanks! Do you have recommendations for other (cheaper) mosfets that are designed for linear operation like the IXTK90N25L2 ?
@oetken0077 жыл бұрын
Great device you build! But does these cheap clamps not giving really small contact points? I would clamp some solderwick between the surfaces to get a lower resistance.
@rancid119999882 жыл бұрын
Very nice!
@zunriya4 жыл бұрын
Can i add more mosfet to increase its heat surface for reduced its heat sources density (more surface more easy to cool it down than small density heat ) ? On pararel
@allthegearnoidea67522 жыл бұрын
100Amps this is awesome
@Mainstream8183 жыл бұрын
Very great project, will be building one soon to test my 24V battery pack. Question about the 19V op amp rail. Is this able to run with a rail to rail voltage of 5V like your previous 150W load? Or is this rail voltage needed because the Vgs of the linear fets are much higher? Thank you for your knowledge and project
@cccyberfamilydk7 жыл бұрын
Great video. Thanks
@donaldhenke27504 жыл бұрын
i like that heah sink. where can i get that heat sink. please.
@tablatronix7 жыл бұрын
Imma steal this! Looks good
@andymouse4 жыл бұрын
Fascinating..cheers!
@songkai19816 жыл бұрын
Nice project, Kerry. Just a quick one, how did you connect MOS-FET's drain pin to the PSU wires? By the contact of screws on each copper plate? Thanks.
@enffinity4203 жыл бұрын
I managed to dissipate 400W permanently with a single FDL100N50F MOSFET that can dissipate up to 2500W
@davidkierzkowski5 жыл бұрын
Good video!
@PelDaddy7 жыл бұрын
Nice job, Kerry. Now you just need to add a uC and a display to do the math as display the load for you. Thanks for sharing.
@KerryWongBlog7 жыл бұрын
Thanks. I will probably do that some time in the future if I get around to it.
@esdblog61007 жыл бұрын
You are operating MOSFETs in saturation region. If they were BJTs than you would operate them in linear region.
@johnconrad54876 жыл бұрын
No. he operating the MOSFET in the linear region same as if it is a BJT
@prabirdebnath51977 жыл бұрын
Hi Kerry, Good Work. I am designing a 500watt DC load. The mosfet you are using are almost identical - I intend to use IXTN200N10L2 . Could you please share the schematic of your design
@KerryWongBlog7 жыл бұрын
Thanks Prabir, the schematics are on my website linked in the description under the video.
@prabirdebnath51977 жыл бұрын
Hi Kerry, Is it necessary to add a reverse polarity diode at DUT end. What if the the DUT is connected reverse, I was wandering whether there is any weak link to destroy the mosfet if the DUT is connected in reverse by mistake.
@KerryWongBlog7 жыл бұрын
The source-drain diode for this particular MOSFET is rated at 90A continuous and 360A pulse, so I don't think you'd need to worry about the MOSFETs.
@davidgaleski53037 жыл бұрын
thank you
@KerryWongBlog7 жыл бұрын
You are welcome!
@prabirdebnath51977 жыл бұрын
Further, on thermal issue, if the mosfet is driven by PWM do you think there will be reduction in heat as the mosfet wont be ON continuously
@KerryWongBlog7 жыл бұрын
Yes, if it's driven by PWM then the power dissipation would be equivalent to the average power dissipation.
@prabirdebnath51977 жыл бұрын
So any plans to incorporate a PWM controller in your circuit in the coming days
@KerryWongBlog7 жыл бұрын
I don't have any immediate plan, but you could easily add a MOSFET that shunts the gate and source of the power MOSFET used for the electronic load and drive the shunting MOSFET with a PWM.
@cheapmod5 жыл бұрын
Wear safety google when playing with mosfet. I have bad experience once which almost blown my left eyes
@DanielsGameVault7 жыл бұрын
Hi it's me again LOL :)) Another question: what about the gate threshold voltage of the FETs ? It's 2v according to the datasheet, yet if you want to have, say 0.075v flowing (let's take the worst case, 100a scenario), can you attain that ? Does this threshold voltage represent the value at which the D-S path is at its lowest resistance ? If I have 0.075v on the gate, will I get 0.075v drain to source and through the resistors ? I read about it many times, but can't quite grasp it unless I try out myself. Cheers.
@KerryWongBlog7 жыл бұрын
The threshold of Vgs doesn't really affect Ohmic region. When the this threshold is reached the MOSFET turns on fully and the resistance is largely dependent on Rdson. By increasing the Vgs beyond the threshold would further reduce Rdson although only slightly. The gate voltage has nothing to do with your Ids, you can reference each MOSFET's datasheet (Vds versus Ids curve for different Vgs) to see the approximately where the operation point is at for a given Vds and Ids.
@johnconrad54876 жыл бұрын
@ Daniel ...... you have to go to at least Vgs = 2 Volts which is the threshold voltage on the gate for the transistor to start conducting. 2V is what is in the data sheet for this FET. there are some that start conducting a lower than 2 Volts and some require a little more. 0.075V across the gate source will do nothing.
@SanjaySharma-pw6ww3 жыл бұрын
👍 like the idea.
@DanielsGameVault7 жыл бұрын
Question: I'm trying to achieve something similar, though for a much smaller load (like 10a max) and I've got those same shunts as you 50A at 75mV, but there's one thing I'm curious about: I see you've got 2 wires on each resistor (one on each side of the resistor). One is the feedback wire that goes to the - input of the op amp, but what about the other one ? The one on the "ground" side of the resistor. The page you linked to explains it's Kelvin sensing and I know what that means, but the second wire is not drawn in your schematic...I may be wrong, so please help me out :D Such a cool device and I need to build my own to stress-test TV power supplies (often they look well under no load but act up when the TV loads them). Cheers.
@KerryWongBlog7 жыл бұрын
Hi Daniel, the other end of the wire on the resistor goes to the ground (as close as to op-amp's ground as possible). This is to eliminate ground loop and ensures the accuracy of the voltage measurements.
@DanielsGameVault7 жыл бұрын
Ok, cool. Thanks for the reply :D YOU HAVE NO IDEA through how many textbooks and designs I went to figure out what that wire does, when all it does is grounding :)) Is it by any chance also going to SHDN pin 5 to disable the shutdown feature ?
@KerryWongBlog7 жыл бұрын
correct, pin 5 of the opamp is also tied to ground.
@DanielsGameVault7 жыл бұрын
Great, it's coming together slowly :D I'll be pestering you a bit more on this build, since I suck at math so thanks for putting up with me :)) Is the following statement correct ? To sink 100A with this thing, you'd need 0.075v flowing through the resistors, since 0.075v divided by 0.00075 ohms (two 0,0015 ohm resistors in parallel and yes, I like to use the "1" multiplier and write down the whole number, otherwise I screw up :)) ) equals 100. If so, the power dissipation would be 7w ? Cheers.
@DanielsGameVault7 жыл бұрын
Correction: 7.5w
@extoprak5 жыл бұрын
Hi, I believe I can do similar load with IGBT instead of MOSFET, what do you think? I have a couple of dual pack IGBT (half bridge). I also have some closed loop current transducer, maybe it is better to use them instead of the shunt?
@KerryWongBlog5 жыл бұрын
Yes, you can use IGBTs as well. Usually though, IGBTs are mainly used for high voltage high current applications, and as a result it comes with rather high Vces which may not be suitable for your application, it all depends.
@johnconrad54876 жыл бұрын
what is the minimum voltage that the load will work at with max current? what is the max amperage?
@KerryWongBlog6 жыл бұрын
It can work all the way down to 1v. Max current I tested was over 100A
@johnconrad54876 жыл бұрын
1V is pretty good. that MOSFET has low Rds. i dont want to spend $ on that MOSFET you are using so i am trying a different device. i am designing one using an IGBT (Vcesat is about 2 Volts) so it is difficult getting down to a low voltage. my minimum has been 2.5V at only a few amps. if i go higher in voltage i can load it with plenty of current but the trick is going down to low voltage and high current. anyway, thanks for answering my queries. not many people do that. :)
@SebastianScholle7 жыл бұрын
NICE! But those mosfets are not cheap.
@ufohunter36887 жыл бұрын
Is there a reason you used such thin wires for current sense and thermistors? None of those readings are accurate if the wires are so thin!
@KerryWongBlog7 жыл бұрын
No special reasons. Those are just the wires I had.
@BikesBlades4 жыл бұрын
The wires used for sensing can be very fine, since they carry almost no current in this "Kelvin sense" connection scheme.
@nbenci90054 жыл бұрын
can be and need to be in order to mitigate external RF interference, thin and short as possible
@stevebliss60565 жыл бұрын
AOT290L a 100v mosfet with a nice SOA (100V @ 5Amps, and 60V @ 10Amps). Way cheaper (about US $3) than the IXYS (US $18). But I do agree, the IXYS is VERY NICE :)
@schwarzarne7 жыл бұрын
You are not operating them in linear region. You really should get the nomenclature right. You operate them in saturation region. Switching happens in linear region.
@KerryWongBlog7 жыл бұрын
Yes, I meant "Ohmic region" instead of linear region. Thanks for pointing that out.
@BikesBlades4 жыл бұрын
The terminology is not very strict. Lots of people use "linear region" to describe the state where the MOSFET is not fully enhanced (working as a source- follower.)