Get rid of your power resistors! - DIY Adjustable Load
Вставка
- Опубліковано 4 жов 2022
- Testing power supplies can be quite tedious if you don't have a dedicated tool to do so. Typically, you would use a wide selection of power resistors to accomplish this task. But there has to be an easier way... right?
-- Links --
My Website: sinelab.net
Schematic: sinelab.net/pdf/adj_load.pdf
-- - Наука та технологія
This is the most underrated channel I've ever encountered. Subscribed with notifications on!
Thanks for watching and thanks for your support! :)
Best explanation
A nice introduction to a simple Electronic Load. Your speech pattern/delivery is improving, kudos! It would have been nice to see the placement of the 45K feedback resistor on the schematic. Speaking of schematics, I suggest that you display (for several seconds) a picture of the final, complete schematic at the start of every video. Tip: In designing a circuit, we will have a goal for its power output... Its voltage and amperage capability. So, we grab a part that can supply so many volts and so many amps. But, that method misses a step. Components can not provide their full voltage and amperage rating, because they have a wattage limit. For example, the IRLZ44N MOSFET in your device is rated for 55V and 47 amps. Multiplied together, you might think that the unit is capable of providing 55V x 47A = 2,585 watts. However, the data sheet shows that this MOSFET is only capable of outputting 110 watts. So, the power output may be adjusted between 110W = 55V x 2A and 110W = 47A x 2.34V. What's the catch? The component's limited ability to withstand heat. As you said, even at 110 watts, the MOSFET needs a large heat sink and maybe even a fan.
Thanks! That's a great tip about the power output. I appreciate it!
Is it essential to amplify the voltage across the shunt resistor? Insted could you divide the setting voltage given to the non inverting input?
I like your videos. Thank you
Thanks for watching! :)
Thats a nifty circuit.. I built myself a electronic dummy load with "just" a PWM circuit and a bank of mosfets & homemade power resistor.. It can handle up to 50A. (video on my channel.) But i will build your desing anyway and give it a try... Greets from Germany..
Excellent! what about a stable voltage Ref chip as a stable supply to the POT
Yes, that would be a great improvement to the design!
I tried following this video, and the written description on the blog, and make my own. But I failed. There is just so much information missing about what connects where ... it is impossible to replicate. Would be great to at least have a schematic or something shown that explains how the whole thing works as a whole, not just different pieces chopped up into a video.
Hey this is neat. I can use this to test some NiMH (and eventual Li-ion) battery charger algorithms, I need a small load to discharge the batteries with, and might as well make a general-purpose one.
Yeah, that's a great way to use this!
Be careful as some chargers disconnect the charged battery during charging cycle and do several measurements on unloaded/ not charged battery to determine state of charge and other parameters.
Cool idea, but what is the maximum voltage and current that a circuit like this can measure/test? What are those parameters limited by? I need a test setup that can handle up to at least 60 volts and up to at least 100 amps, so as far as I know, I'm still limited to using multiple separate, high wattage power resistors in various series/parallel combinations to test that much power from a power supply, or from a very high wattage audio power amp too, all without negatively affecting any amplifier's output sound quality either. (Which I'm not sure if a MOSFET and op-amp circuit could achieve)
This circuit is mainly limited by the MOSFET. Your setup might be possible, but the requirements are extremely high. 60V at 100A is 6000 Watts. So you would not only need to find a MOSFET that could handle 6kW, but also find a cooling solution for that. At that point, it's likely easier to just get power resistors.
@@SineLab Yeah, I figured as much. Maybe multiple MOSFETs in parallel somehow, upping their total current capacity, could then handle that kind of power? (I just don't know the best way to actually do that.)(I'm also still not sure if a MOSFET and op-amp electronic circuit like this would interfere with or have some kind of electrical "issue" with testing an audio power amp's output either, since it isn't a totally passive circuit like just plain power resistors are. I wouldn't want to short something out in either the amp OR the test circuit!)
I wish I knew more about this without actually having to build and try it myself and then (potentially) having it damage one of my amps or something else. :/
I hope you’re taking some medication or seeking some form of treatment for your respiratory issues. Not something to ignore or wait till it gets worse.
I don't have any respiratory issues as far as I know.
Don't write! prepare the drawing beforehand- you are no Einstein
I did prepare it beforehand. I'm just drawing so that you can see the design process.