Scullcom Hobby Electronics #56 - Electronic DC Load Part 8

[@BryanByTheSea]

Your videos really show the love of the hobby. Thanks so much for taking the time to produce these. Thumbs up

[@scullcomhobbyelectronics1702]

Thanks Bryan for your kind comment, much appreciated. Regards, Louis

[@colindejager1250]

Hi Louis I managed to obtain one of the pcb's, and started to build the circuit. First thing was to solder in all the surface mount ic's - which needed a microscope! Next I put in the parts for the ref voltage module, and set the voltage to about 4.096v Using an Analog Discovery 2 (probably a logic analyser etc), I then tested for I2C addresses When I received them, I sent the device code and address with the Read bit set, and a general reset command This was sent to all devices seperately, to check I could communicate - I can!!! All good to continue.... Thanks again for this amazing project; for learning as well as using to achieve more goals...

[@scullcomhobbyelectronics1702]

Hi Colin, Nice to hear you are progressing well with your DC Load. Regards, Louis

[@peteb2]

Ordered my board 3 March, arrived Auckland, New Zealand in my letterbox 9 March.... FANTASTIC service! (The project starts in earnest... waiting now on Element 14 NZ to consolidate my parts request)....

[@scullcomhobbyelectronics1702]

Hi Pete, That was quick. Must have come via a rocket :-) I would appreciate it if you could mark it as delivered on eBay for me. Regards, Louis

[@peteb2]

Thank you Mr Scullcom. I've been needing a DC Load that isn't overly simple in what it offers while the professional units are just too expensive. One PCB on its way to New Zealand.

[@scullcomhobbyelectronics1702]

Thanks Pete, Not sure how long it takes to get the New Zealand. But let me know when it arrives. Regards, Louis

[@brucewoods9377]

Loved this update and have added it to my DO LIST. Well explained and demonstrated as with all of your projects and posts. Looking forward now to your XR-2206 Function Generator update.

[@scullcomhobbyelectronics1702]

Thanks Bruce. Regards, Louis PS: I think I click on a wrong button :-)

[@dapreygerard8981]

Hello Louis Scully Well received the PCB this morning as agreed Very good work, quality with plan in accompaniment. What to say, congratulations again for your professionalism on this project. I'm going to work. Bravo again. Gérard Daprey

[@scullcomhobbyelectronics1702]

Thanks Gérard.

[@tonybell1597]

Louis, superb job! PCB ordered! looks like the one I have been building will get a re-work! Many thanks indeed, keep up the excellent work....

[@scullcomhobbyelectronics1702]

Thanks Tony, the PCB is on its way to you. Regards, Louis

[@charlesbickenheuser8281]

The quality of Your PCB's is Super. Thank You

[@scullcomhobbyelectronics1702]

Thanks Charles. I will let you know when I have the new batch of the DC Load PCB's. Regards, Louis

[@charlesbickenheuser8281]

Thank You

[@scullcomhobbyelectronics1702]

Hi Charles, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@qzorn4440]

o my this is a great covid winter project...🤒 yes circumstances have changed in 2022 🧐i luv watching the project develop 🥳i am thinking esp32 bluetooth 🤩thanks a lot ⛷🌴🎂☕

[@markuscwatson]

What a great series! I hope you make another series like this for another cool project!

[@scullcomhobbyelectronics1702]

Thanks Mark. Will see what we can do. Regards, Louis

[@esnam6557]

Great Improvement, I like keypad 4x5 although prefer to glue the pin t othe board or drill a hole into the board for the extra pin if possible. Thank you very much for sharing all the info + The double sided PCB

[@scullcomhobbyelectronics1702]

Thanks. yes you could glue that pin to the PCB. Regards, Louis

[@Brian_Of_Melbourne]

Hi Louis, Given that you are printing out a new overlay for the 5 by 4 keypad, there is no longer any need to use the keypad in its original orientation. Specifically, the wires can emerge in any direction (north or south if you like). You could even use it in landscape rather than portrait (wires emerging east or west). This might allow for a more obvious layout: 7 8 9 Bat Curr 4 5 6 Trans Power 1 2 3 Limits Res DEL 0 . Enter On/Off Cheers, Brian.

[@scullcomhobbyelectronics1702]

Hi Brain, Thanks for your comment. Yes agree you can have the keypad layout anyway you wish. Simply just print a different overlay and change the Arduino code to suit. Regards, Louis

[@wolfgangschweiger9557]

As always - great work! I'm still on working on my version of your load, but the route is the goal ;-) Greetings...

[@scullcomhobbyelectronics1702]

Thanks Wolfgang. Regards, Louis

[@topphemlig1191]

Great video and you've worked extremely hard on such a nice pcb update. Absolutely superb, thanks for sharing

[@scullcomhobbyelectronics1702]

Thanks, it did take a while and I went through a few prototypes before finalizing the PCB. Regards, Louis

[@brainfornothing]

Your work is always exceptional and very well explained ! Thanks a lot !

[@scullcomhobbyelectronics1702]

Thank you.

[@randycarter2001]

Nice circuit. There's one thing I would like to add. If you plan to use this thing testing batteries add a JS1 series relay to the plus input. Batteries are never off and you want a backup turn off method. Just in case something goes horribly wrong.

[@scullcomhobbyelectronics1702]

Thanks for your comment. Regards, Louis

[@MrMickjbriggs]

Superb update, thank you. PCB Ordered.

[@scullcomhobbyelectronics1702]

Thanks Mick. PCB is on its way -;) Regards, Louis

[@MrMickjbriggs]

Received Louis, many thanks. Looking forward. to building this.

[@niaceri1]

Hi Louis, Thank you so much for this project (and your other series): you are a great teacher, and you have helped rekindle my interest in electronics as a hobby. i have completed the build of the DC Load - and it mostly works extremely well...I have been able to get a reasonable degree of accuracy. ...but i have a problem which i am struggling to fix. When the fan switches on it impacts the circuit to such a degree that - the power rails fluctuate : strangely (?) the 5V rail seems to temporarily increase in voltage ...and this alters all the values internally : the measured temperature "drops" a couple of degrees; the controlled current changes; the "read" voltage changes. The apparent "drop" in temperature means that the fan immediately switches off - the system thinks that it is

[@scullcomhobbyelectronics1702]

Hi Dave, This issues seems to be cause by some grounding problems on the underside of the PCB. When the fan/fans turn on the extra current on the power lines is causing a very small voltage drop on some sections of the grounding/earth return lines on the PCB print. I am just working on an update video for this project in which I will address this issue and should be uploading the video soon and discuss some other improvements. Adding some additional grounding on the underside of the PCB solves this issue - I will demonstrate this in the video. I am preparing some additional documentation on implementing this extra rounding and will supply it as a download on my next video. Regards, Louis

[@niaceri1]

Louis, Thank you so much for taking the time to consider this and to respond ...your responsiveness is so much better than some of the paid service providers that I use in business :-) I do appreciate it. I am looking forward to seeing a possible resolution ...my current (no pun intended) thinking is to have the fan turn on permanently at start-up, and allow the voltages to "settle" ...it does mean continuous noise and a quieter alternative would be great. Thank you!!

[@TheFunkman]

I have one by another seller but it has a few bugs. I like yours better so far. Keep it up!!

[@scullcomhobbyelectronics1702]

Thanks Rudy. Regards, Louis

[@scullcomhobbyelectronics1702]

Hi Rudy, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@isidoromaich7226]

major improvements, excellent video, thanks

[@scullcomhobbyelectronics1702]

Thanks.

[@23RaySan]

man, this PCB looks really nice. I think im going to ditch my design and use yours. Thanks for sharing!

[@scullcomhobbyelectronics1702]

Thanks Ray.

[@lordmarshall1139]

always good stuff man

[@scullcomhobbyelectronics1702]

Thanks Lord.

[@AIexanderHartdegen]

Hello, can someone tell me how is the nature of signal sended to the MOSFET gate? Are they proportionnal? Linear? Pulsed? Dutycycled? Or switched due to the flip flop effect of "reach avalanche point"? Thanks a lot

[@priestblood]

Hi fantastic videos ,do you have any more PCB's I can purchase. Thank you

[@mancelprince7426]

First, thank you. I have built the version you did in video #7. It powers up, shows the Scullcom splash screen and goes to the initial screen as it is programmed to do but I haven't had time to test it yet. Question? In part #8 you changed R39 and R43. Why and should I change my existing R39 and R43 to the newer values?

[@scullcomhobbyelectronics1702]

Hi Mancel, The only reason I changed the values of R39 and R43 was to improve the zero reading of the actual voltage and current readings on the LCD. If you find the original values work OK for you in Part 7 version then leave them as they are. If you find that the readings are not go to zero them make the change. Regards, Louis

[@rebelba42]

What a great project, many thanks for sharing this! But I'm obviously late. After one day all PCB's sold out. Please let me know, if you have new PCB's in stock, at least one for me :D Again thanks for doing this great DC-Load series!

[@scullcomhobbyelectronics1702]

I have just ordered a new batch of PCB's and should have then in 7 days. I will reserve one for you. Let me have your email address in Private Message section of You Tube. Regards, Louis

[@scullcomhobbyelectronics1702]

Hi Reb, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@rebelba42]

Hi Louis, got one a minute ago, many Thanks! And thank you for doing this. I've learned a lot from your videos and projects.

[@rebelba42]

Hi Louis, PCB just arrived to Germany. My Wife "Jamila" was wondering about the PCB :) Now I have to build it. Thank you, you're very kind!

[@killer_x_treme]

HI I see you made this video a few years ago. I'd like to make this project as I need an electronic load. Do you have any more PCB's available? The ebay link doesn't work. Perhaps also the pcb files so I can order them myself if you are out.

[@khuseyin123]

Great video.Thanks.Informative video.

[@scullcomhobbyelectronics1702]

Thanks.

[@avejst]

Thanks for sharing, Nice job - as always :-)

[@scullcomhobbyelectronics1702]

Thanks Asger.

[@CliveChamberlain946]

Great update, thanks! Question: Is D5 really required? Mosfets have body diodes and it may be somewhat limiting at LV. In such cases, what effects on calibration would bypassing D5 and the fuse with an intermediate binding post?

[@scullcomhobbyelectronics1702]

Thanks Cliff for the question. The body diode of a power mosfet does provide some form of protection. If your load was connected in reverse the mosfet body diode would conduct and you would have maximum current flowing through the mosfets for a short time unit the 5 amp fuse blows. Therefore the fuse should in theory protect the power mosfets. In some of my early experiments with this DC load I did test this option but I found on some occasions one of the 4 power mosfets failed. So as to prevent this I added the series dual power Schottky Diode (connected in parallel) - in this instance protection is provided without blowing the fuse as no current flows through the mosfets under reverse load conditions. I also noted that some commercial DC Loads also used a similar technique. I have not found the very small voltage drop across the diode to effect calibration. Regards, Louis

[@TheRcEngineer]

Hi thank you for the great work my load is nearly finished,just need to source a 4.7m resistor. You could install a uno boatloader which is better and frees a k of ram.

[@scullcomhobbyelectronics1702]

Thanks for the tip on the bootloader. I did not realise the Uno bootloader was different to the Nano. Regards, Louis

[@Djinnsos]

I am in the progress of: "making the aluminium front panel / having it cut to size, and I am wondering what thickness aluminium you used for this? Thank you once again for this great project With regards Martin

[@scullcomhobbyelectronics1702]

Hi Martin, The aluminium front panel thickness I used was 2mm. However, you may also find that 1.5mm may be suitable as it will be well supported in the case surround. Regards, Louis

[@EdwinFairchild]

what are the voltage references used for?

[@alexeicebanu7987]

For ADC or DACs is better to use stable and precise voltage reference if you want to have good accuracy.

[@EdwinFairchild]

@@alexeicebanu7987 I see, thanks!!

[@alexeicebanu7987]

​@@EdwinFairchild but, but... you already knew that right? :)) your name was seemed familiar to me and then, i realised that I am already subscribed to your channel! :D Cheers!

[@EdwinFairchild]

@@alexeicebanu7987 I know enough to know I don't know much. 😔

[@drulli1]

Great improvements! Directly after having watched the V8 vid I tried to purchase one of them. Unfortunately they are sold out already. Too bad. Any chance that you order another set or provide the needed gerber files to order them buy individually?

[@scullcomhobbyelectronics1702]

Thanks. Sorry you missed out on the first batch. I was very surprised how quick they all went. I have just ordered another quantity from my PCB manufacturer today and should have them in 7 days time. I will put them on eBay and give a new like in the comments below my video. If you want to send me your email address in the Private Message section of You Tube I will reserve one for you. Regards, Louis

[@stevecooper1537]

Scullcom Hobby Electronics Hi Lois Could you reserve me a pcb please. Regards Steve Cooper

[@scullcomhobbyelectronics1702]

Hi Steve, Yes I will reserve one for you. I should have the new batch in 6 days time. If you are able to contact me in the Private Message option of KZbin with your email address that would help. Regards, Louis

[@stevecooper1537]

Hi Louis I have been trying to figure out how to send a pm but after 3 hours of trying to figure it out, I have given up so here is my email address. [e-mail]

[@scullcomhobbyelectronics1702]

Steve I have sent you an email. Regards, Louis

[@MrHD71]

Nice! I've a question? How long must one study electronic engineering to create such circuits?

[@scullcomhobbyelectronics1702]

Interesting question ;-) I started electronics when I was in my teens as a hobby, a long time ago. I then studied at college for 6 years. But the simple answer to your question is if you are really interested in electronics and spend time understanding the basics and practice building electronics projects you will soon progress to making your own basic designs and move on from there - it is really down to you, the time it take varies from person to person. But the important thing is enjoy what you do. Regards, Louis

[@ManofCulture]

You don't have to be an engineer to do it :D. For beginners, make first a circuit that is a simple one, then going to complicated.

[@electronic7979]

Excellent

[@scullcomhobbyelectronics1702]

Thanks.

[@tsmupdatertsm7633]

18:20 what is the reason for "studoff" the power resistors on the PCB ? Can you damage something when you don't "studoff" them ?

[@scullcomhobbyelectronics1702]

No you will not damage anything. They could get a little warm at very high current loads so it is just a precaution and good practice. Regards, Louis

[@tsmupdatertsm7633]

thanks

[@Ocelot-qx2fy]

Great work sir! I think I did not get it. could you tell me what is the max continuous power limitation of your dc load ?

[@scullcomhobbyelectronics1702]

Thanks. The design as it stands allows currents up to 4 amp and load voltages up to about 50V so in theory the maximum power could be around 200 watt. Sofar I have tested it to about 120 watt and it was OK. At the higher wattage you need to ensure you have a large heat sink and a good quality fan cooling the heat sink. Regards, Louis

[@alanlondon8830]

Well, I've been watching eBay and was hoping to get a PCB for this but all sold in ~2 hours!! Will there be any more or have I missed the boat?

[@scullcomhobbyelectronics1702]

Hi Alan, Yes I was surprised how quick they went! If you send me a private message in You Tube with your email details I should be able to help. Regards, Louis

[@dutchmhk]

Bugger!! I am too late for the PCB. Scully Please add more PCB´s on Ebay :-) Or as my son usually says when he want´s candy..."pretty please"

[@scullcomhobbyelectronics1702]

I have just ordered a new batch of PCB's and should have then in 7 days. I will put them on eBay when they arrive. I have sent you an email to your gmail account. Regards, Louis

[@DavidSkilton]

I'd love to build one of these, but the PCB's have again run out. Are you planning another manufacturing run?

[@scullcomhobbyelectronics1702]

Hi David, Saw your request for a PCB on my website. I have ordered a new batch and should have them in about 6 days time. I have sent you an email with details. Regards, Louis

[@Djinnsos]

To slow to buy once again, well I hope you have some more on the way? With regards Martin

[@scullcomhobbyelectronics1702]

Hi Martin, If you send me a private message in You Tube with your email details I should be able to help. Regards, Louis

[@NEXTLABS-w2m]

Does anyone know what happened to Mr. Louis Scully, because for several years he has stopped writing and no longer uploads anything new .... ??

[@mohammedafeed117]

I can't download schematic Can you help me

[@ChrisSavageEngineer]

The ZIP files don't seem to be available. Does anyone have an alternate link?

[@tntodorov]

I wonder if it would be a good idea to make the load switchable through a relay, which is normally open. This way it is guaranteed that nothing will be driving the drains of the MSOFETs, if you forget the power supply under test plugged in, while to DC load is off...

[@scullcomhobbyelectronics1702]

Hi, Thanks for your comment. Yes this could be an option. However, the current design of the DC Load already ensures that there is no drive voltage supplied to the Power Mosfets so effectively it is already off at switch-on. But you could add a relay as a fail safe option if you wished. Regards, Louis

[@kitmanevo]

Τhere seems to be a 8-9 mA leakage current while the load is off. But the lcd on the DC load shows zero amps. Where does this current come from. Any ideas? Very impressive project by the way.

[@scullcomhobbyelectronics1702]

Yes there is some small leakage current which I zero in software for the LCD display. It is possible to remove this leakage down to 0mA but then I found it effects the current reading on the low current settings below 200 mA. This seems to be due to the DAC (U5) accuracy at the very low settings. I will have another look at that and see if there is a solution to overcome the DAC zero offset error and the DNL error. The current Null preset (RV3) can be adjusted to improve this error. At the moment the current settings are OK from about 100mA to 4 amp with only a very small error of a few mA. I will have another look at this later. Regards, Louis

[@kolesar0007]

Hello, really great project. I want to order PCB but was already gone :(. Is there another batch of PCBs on the way? BR Sandi

[@scullcomhobbyelectronics1702]

Hi Sandi, I have already sent you an email following your request on my website www.scullcom.uk Regards, Louis

[@Arek_R.]

All PCBs sold haha. You have to order like 100 of them, please! :D

[@Arek_R.]

PS in my simple electronics load I made few years ago, I used SUP57N20 n-mosfet from VISHAY, was able to dissipate about 200W at 12V at only one piece! I achieved it by soldering the mosfet directly to copper IHS salvaged from old CPU, and then attached it to old AMD CPU cooler, also used good quality MX-2 thermal paste. Swap that old crusty cooler with something modern that uses heat pipes, like thermaltake macho, get bigger piece of copper so you can solder like 10 mosfets, and I would expect it to handle like 600W.

[@Arek_R.]

I think I will make this, but I'll change mosfets to these I mentioned above and replace 20x4 screen with 3,2' graphical display with touch screen from nexion, it has built in STM32 uC doing all the hard work and communicates via I2C.

[@scullcomhobbyelectronics1702]

I have just ordered another batch of PCB's. Should have them in about 7 days time. Regards, Louis

[@Arek_R.]

Thanks for the reply! Such a schame that I don't really have the time and conditions to build this(moved to another country) :/

[@billigerfusel]

Beautiful

[@scullcomhobbyelectronics1702]

Thanks.

[@billigerfusel]

Scullcom Hobby Electronics continue what you're doing. So easy to learn from your videos.

[@flemmingchristiansen2462]

When in tracient mode, there could be long periods for on and off time, would it be useful with a countdown function?

[@scullcomhobbyelectronics1702]

Thanks Flemming for your comment. That could be an interesting option for long transient times. Could be a future upgrade. Regards, Louis

[@deathblowhere]

Hey Louis! Simply the best DIY load! In my opinion it's as good as commercial BK precision 8500 series ones. I wanna re-disign a circuit a bit to provide 100V / 25A capability. I plan to use four IRFP250NPBF 250v/30A mosfets and, I think, it's gonna be a nice compliment to your device. Also I consider about using 8 power devices instead of 4 for better power dissipation. Are there any "traps for young players"?)) Thank you very much! Regards, Phil

[@scullcomhobbyelectronics1702]

Hi Phil, Thanks for your comments. I have looked at using the IRFP250NPBF for the 4 Power Mosets myself. However, as they are not Logic Level Mosfets they will require a higher gate/source drive voltage. To achieve this I have looked at replacing the U7 (Quad Ultra Low Voltage Offset OP Amp) AD8630 (which can only operate to a maximum of +6V Supply) with a AD8664 which can operate at a higher supply voltages, you could then feed it with the +12 supply. As the pin layout are identical to the it is a drop in replacement for the AD8630. If using my PCB you would then need to cut the track from pin 4 of U7 (+V pin) and then connect Pin 4 of U7 to +12V supply with a wire. This should then give you the required gate drive voltage for the IRFP250NPBF. I have not tested this option yet but I may give it a try. The IRFP250NPBF is a TO247 package compared to a TO-220 package of the BUK956R1-100E, which would need to be taken in to account. Regards, Louis

[@deathblowhere]

Thank you much, Louis! Really looking forward to build this project! Also one more thing. As I wanna implement 25A capability, voltage across R17 will be 25A*0.1R = 2.5V, not 0.5V as it is in your initial design. Should I change R6 and R14 dividing resistors (for example make R6 - 1k and leave R14+RV4 as they are - 909R + 200R) to achieve a voltage control range of 0-2.5V? Cheers! Phil

[@scullcomhobbyelectronics1702]

Hi, If you are looking to have a maximum of 25A then I would suggest using a lower value sense resistor for R17 would be better. If you replace R17 with say a 0.02ohm 10 watt 1% resistor then at 25A the voltage across it would be 0.5 volt. The change in voltage then fed via buffer U7D to the ADC (U6) wound need to be compensated for as you are now using a lower sense resistor, this could be done by setting the gain of channel 2 of the MCP3426 in software to a gain of 8 (instead of the current setting of x4) and also making some changes to the code where the calculation is made for the current reading on the LCD. With regards the resistor divider R6, R14 and RV4. Try changing R6 to say a 27K and R14 to a 1K and RV4 to a 1K preset, to ensure you have sufficient range. Regards, Louis

[@deathblowhere]

Man, Thank you! I'll definitely go this way ;) Regards, Phil

[@andymouse]

Hi did you finish this 5 years ago and is it still going strong please ??@@deathblowhere

[@georgelivanes2832]

Hi Louis, Love your really useful projects and your excellent background info of the circuits. Missed out on your double sided PCB offer on ebay. Will you be offering more PCs in the future?

[@scullcomhobbyelectronics1702]

Hi George, I have ordered some more DC Load PCB's. If you can send me a message with your email address in You Tube private messages I will reserve one for you and keep you updated. Regards, Louis

[@juliusvalentinas]

You forgot to post the specifications Amps. Volts, Watts etc. for the current version! Great job on the PCB, I hope the 8-9 mA leakage current while the load is off is fixed soon. This will require new PCB right?

[@scullcomhobbyelectronics1702]

Hi Julius, The specification for the current version of the DC Load is: 4 Amp (maximum) 50 Volt (maximum) 120 watt (maximum) I have found that the Power limit of 120 watt may be increased by using a larger heat sink and two fans. I have had the unit currently operating reliably at 3 Amp at 30 Volt (90 watts) on its current heat sink and one fan (heat sink temperature monitored at between 50 to 60 °C when running for more than 10 minutes). I will be looking at ways to fix the small 8-9 mA leakage current while the load is off (on the current PCB version 9.2) and will cover this shortly in an update video on this project - basically the Current Null preset (RV3) can reduce the leakage current to zero but may effect the calibration slightly. Regards, Louis

[@brucewoods9377]

Tried to purchase this pcb, but site said it did not ship to Australia. Now they are no longer available. How can I obtain one please?

[@scullcomhobbyelectronics1702]

Hi Bruce, I have just ordered a new batch of PCB's and should have them in about 5 days time. If you go to my website www.scullcom.uk and leave a message there then I will be able to contact you by email and arrange a PCB for you. Regards, Louis

[@tarasprindyn7415]

Hello, very nice DC load, and just want to add CV mode! How do you think, is it possible? Can you add it?

[@mancelprince7426]

I assume that CV is constant voltage. Not practical. Think about it and I am sure that you will see. This is not a power supply. It is a load. A battery under test is simply what it is. The same is true for a power supply under test. I am not the most knowledgeable tech around and if I am wrong I hope that someone will enlighten me.

[@scullcomhobbyelectronics1702]

In Constant Voltage (CV) mode operation, the DC Load must attempt to sink enough current to maintain the set voltage. However, a DC load will have limitations on how much current it is able to sink. Therefore, CV mode would not really be practicable in this project without adding limitations which would then defeat the purpose of having a CV mode. I agree with Mancel's comment. Regards, Louis

[@tarasprindyn7415]

Thanks a lot, now I undrestand you and agree with you and Mancel.

[@mirkozaccagni7657]

Thank you Louis, the pcb on ebay are all sold out can you upload the files?

[@scullcomhobbyelectronics1702]

I have just ordered a new batch of PCB's and should have then in 7 days. If you send me your email address in the Private Message section of KZbin I will email you when I have them and I could reserve one for you if you wish. I will also put them on eBay again. Regards, Louis

[@mirkozaccagni7657]

Scullcom Hobby Electronics ok thank you very much... How i can send a pm?

[@scullcomhobbyelectronics1702]

Hi Mirko, I will reserve a PCB for you. You will find details how to do it here: support.google.com/youtube/answer/57955?hl=en-GB Regards, Louis

[@scullcomhobbyelectronics1702]

Hi Mirko, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@nk357-00]

Scullcom Hobby Electronics too late... Any chance for another batch?

[@PL-VA]

These are hard to get "NXP BUK956R1-100E MOSFET Transistor, N Channel" - do you have an alternative?

[@scullcomhobbyelectronics1702]

Hi Peter, I have seen them available on eBay. But one alternative could be the STP80NF55-06 from ST Microelectronics but it maximum voltage rating is 55V (compared to the 100V of the BUK956R1-100E). I do mention alternatives in Part 5 of this project at 34.45 minutes. I have sent you another message about this with your PCB order. Regards, Louis

[@CliveChamberlain946]

A guy on EEVblog used IRLB4030PbF (it's rated for 100v) you can see it here: kzbin.info/www/bejne/aGTSmomFfrGaqqc

[@proluxelectronics7419]

That TIP122 collector tab looks close to shorting to ground via USB connector shell..

[@scullcomhobbyelectronics1702]

Hi Mike, When you bend it down its OK some 5mm of more from that USB connector. You could also leave it standing vertical if you wish but then it blocks access to the USB connector if you want to re-program the Nano. Regards, Louis

[@charlesbickenheuser8281]

SOLD Thank You

[@scullcomhobbyelectronics1702]

Hi Charles, I have another batch of DC Load PCB's on order should have them in about 7 days. I see you ordered another pair of the DC Voltage Calibrator PCB's which I have just packed up ready for the post tomorrow. Regards, Louis

[@scullcomhobbyelectronics1702]

Hi Charles, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@johnnz4375]

Hi, are you getting more of these PCB’s ? I tried to sent you a private message but that option is not available under your “about” tab. I also left a message on your website, that has my email on it. Regards, John

[@scullcomhobbyelectronics1702]

Hi John, I have just seen your message on my website and sent you an email. I have just received a new batch of PCB's today. Regards, Louis

[@Graham1904]

I think you have a problem with your temperature of the heating. ... 6 Deg C ?

[@supyrow]

Im building this one for sure! keep an eye on my channel for updates on that. Thank You for this great video!

[@scullcomhobbyelectronics1702]

Glad you liked it ;-)

[@Gooberslot]

Are you not going to offer the PCB files this time?

[@scullcomhobbyelectronics1702]

I will be providing PCB files later. I have just ordered another batch of PCB and should have them in 7 days time. Regards, Louis

[@lordmarshall1139]

good stuff

[@scullcomhobbyelectronics1702]

Thanks.

[@isprithul]

Please tell me the dimensions of this PCB. Where can I find the layout?

[@scullcomhobbyelectronics1702]

The DC Load PCB dimensions are 137.5mm * 134mm. Regards, Louis

[@isprithul]

Thanks

[@TheDefpom]

I’m surprised that you put the sense resistor onto the same heatsink as the mosfets, as the heat generated would effect the resistance of the sense resistor slightly, throwing off your current reading slightly. Otherwise this is a very impressive project.

[@scullcomhobbyelectronics1702]

Thanks for the comment. In practice I have found it has little effect. You could if you wish un-bolt it from the heat sink and bend it towards the PCB. Regards, Louis

[@daveg2578]

Great channel and presentation. If my teachers back in high school had had the same approach, the last 35 years might have been some what easier! Seems the NXP Mosfet is discontinued. can anyone confirm this as a suitable equivalent please... IRLB4030PbF . Thank you.

[@ivolol]

Might be okay, firstly the IRLB4030 has very slightly higher Vgs characteristics, but should still be fine for 5V operation. The bigger problem is the safe DC operating area graph, for the BUK this stretches all the way from 10V/11A out to 100V/.7A, for the IRLB they cut it off at basically 10V/10A and it barely goes past that.

[@bfx8185]

My suggestion is to change your UI to in transient mode, move your information up, and in 4th row put the message "Do you accept this changes?" because now its not so clear what you are doing. You have 4 lines, let's inform user about current state.

[@scullcomhobbyelectronics1702]

Sorry not sure exactly what you mean about "change your UI to in transient mode" Regards, Louis

[@flemmingchristiansen2462]

Good to see you back . It is truly a great pleasure to follow your projects, I am learning a lot and remembering forgotten learnings from my old schooling(30 years ago). Following this project I have learned how much i need this DC Load, unfortunatly iI was to late on EBAY to get the pcb, would you please reserve a pcb for me?

[@scullcomhobbyelectronics1702]

Thanks. Yes I will reserve one for you. I should have a new batch later this week. Will send you one when they arrive and we can arrange payment by Paypal. I see you have just ordered the DC Voltage Calibrator PCB's - I have just pack them and will post them to you first thing tomorrow morning. Can you give me your email in the private message here in You Tube so I can contact you. Regards, Louis

[@flemmingchristiansen2462]

Thank you for the quick response. About the private message -how to do that?

[@scullcomhobbyelectronics1702]

check out the following link: support.google.com/youtube/answer/57955?hl=en-GB In addition I did put an information sheet also with the DC Voltage Calibrator PCB's I am sending you which also has my email address on. Regards, Louis

[@flemmingchristiansen2462]

Thank you for the link, working fine. Best Regards, Flemming Loua Cristiansen

[@abeleski]

Great update thank you. Wish you had given us the gerber files. The pcb is sold out 😟

[@scullcomhobbyelectronics1702]

I have just ordered a new batch of PCB's and should have then in 7 days. If you send me your email address in the Private Message section of KZbin I will email you when I have them and I could reserve one for you if you wish. I will also put them on eBay again. Regards, Louis

[@scullcomhobbyelectronics1702]

Hi, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@abeleski]

thank you

[@abeleski]

that link tells me the listing has ended.

[@abeleski]

haha. they all sold out already.. bugger. :) not to worry. thanks anyway

[@TheMockTv]

I can't understand why you use a keypad and not the rotary encoder in your software it would make everything so much easier and save space and the next thing I can't understand, why you don't automatically switch from mA to A in the software

[@terjesjomark4349]

Hey.I would like to buy a Electronic DC Load PCB from you. Could you reserve one for me if you plan to make more of them?BR Terje.

[@scullcomhobbyelectronics1702]

Hi Terje, I just got a new batch in today. I have reserved one for you. I have sent you an email about it. Regards, Louis

[@vk2amv]

Are the PCB's going to be listed on ebay again soon? I am also wanting to make the DC load and would like to grab a PCB.

[@scullcomhobbyelectronics1702]

Hi, just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@vk2amv]

Scullcom Hobby Electronics awesome thanks. I have ordered a couple, one for myself and when I mentioned it to two makes over here in Australia they said they would like to build one too so we are all set.

[@tablatronix]

wow this has gotten so much more complicated , lol

[@scullcomhobbyelectronics1702]

mmmm ;-) Regards, Louis

[@G0WZB]

There gone already :-(

[@scullcomhobbyelectronics1702]

Yes I was very surprised to. I have ordered a new batch. I have sent you an email about them. Regards, Louis

[@G0WZB]

Thanks Louise

[@MrOrangeman18]

No more left on Ebay. Sad face

[@scullcomhobbyelectronics1702]

Hi, I have a new batch of PCB's on order and should have them in 6 days time. Would you like me to reserve one for you. Regards, Louis

[@MrOrangeman18]

Scullcom Hobby Electronics hi Louis. Il keep an eye out on Ebay and purchase one if that’s easier? Many thanks. Steve

[@scullcomhobbyelectronics1702]

Hi, Steve, Just listed 10 available on eBay link below: www.ebay.co.uk/itm/292478375166 Regards, Louis

[@fellpower]

Your video is soo old, that most of the components u use, u cant buy anymore....