How to measure power supply ripple
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- čas přidán 13. 11. 2017
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IN this video we look at how to measure ripple and distinguish it from noise when looking at power supply output.
Yeeco DC DC Buck Voltage Regulator Power Converter - amzn.to/2iTNMsm
5A DC-DC Adjustable Step-Down Buck - goo.gl/EuCMni
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Very interesting that the noise to noise spread on both power supplies was exactly the same. Must be something in your home wiring or what ever you were using to power the different supplies. Really cool demo. Great proof that you should always check out the characteristics and quality of the different parts you get when doing a component build. Thanks for the wake up.
+Carl Davis Yes, the noise is common mode. It comes from the same power supply, powering both of those converters. Very good observation.
@learnelectronics Hi, you should try to use the small spring with your probe (some people call it paperclip method) and compare your results. The ground wire in your probe creates ground loop.
Few weeks ago I was measuring made in the US commercial grade, 24V DC -> 5V DC buck converter. When I used probe with the wire I observed about 200mV ripples at ~150kHz. When I used the paper clip method the ripple dropped to to ~15mV, huge difference. The ground loop works as antenna.
Great great explanation . I have grasped so much in watching this :-)
Thank you
Great video, you won a sub.
Nice video!
Oh you have made a video about this thanks!
Thanks for sharing..
Hi, great video!
Just one question regarding the Vpp.
You measured the ripple Vpp, how about the noise Vpp?
Is that not important comparing to the ripples?
Much appreciated!
I just checked an old Micronta Solid State Linear variable power supply at 9 vdc. If I did the process correctly (used an LED and resistor as the load), the ripple is 16mv at 10Hz according to my oscilloscope. I’m learning how to use the oscope also.
Very informative video! So those bursts of noise always happen where the original signal would pass through zero?
+Michael Eckl They can happen at any point. They are artifacts of an SMPS.
I guess the old adage "you get what you pay for" is still true. I should measure my bench supply and see how clean it is. Thanks for the tip, I think I'll put it to use.
+George Chambers Yeah, let me know the results. It it linear or switch mode?
It's a Mastech HY1803D just a little 30V. It is linear though. Seems to work quite well so far, I've had it a couple of years.
ya probably not really seeing much if anything useful. look at it through a spectrum analyser. a cheap way is to bang it onto your PC soundcard through a coupling capacitor and optional transient clipping diodes. it'll get you 96khz range only depending on your card but its a start.
Hey, I think I have that same O-SCope. Well at least the same brand
Ahh great video on a very interesting subject. Would have been nice to see a linear voltage regulator as another example (i believe this would have far less ripple than the buck converters).
+Michael Padovani You are correct, the linear supply may have only 10s of mV of ripple.
If you add a electrolytic cap and a ceramic cap will it reduce the ripple?
What about a 5 buck dollar converter? You have any of those? But really, is there an easy way to clean up those signals? Some kind of filter or circuit?
would a cap help the noise? or cap and inductor? on the first buck conv....
also I need to run some 12 v led strips. about 6 lights. or strips. maybe 8, but I have a 24v bank. what do you think would be most efficient. run 24v to the room where the lights are. then drop to 12v. with multiple buck converters
or a single higher amp converter mounted near the batt bank. also I was thinking about a kinds ups. have a small 12 v lithium battery. using the 24v as the main power. and to charge the lithium. I don't want to get complicated. I just need lights even if the large bank is dead. but that can wait until later . I need to get lights for now. so I need about 2 a per strip. or about 20amps max. because I may want to go with rgb or rgbw. led strips.. I don't usually have a lot of brtght lights on . I tend to stay in dim light. unless I'm trying to do something. or reading. so they will not be on fully. so maybe a central mounted mid wattage would work. 10-15amps. great video. I never thought a buck converter could be so noisy .
+James stranger It's not that the buck converter is noisy, it's the switch mode power supply powering the buck.
As for you, one large converter.
the buck converter will create noise if it switches. the noise you see eventually on the power rails will be an intermodulaton of both the power supply and buck converter's switching frequencies.
take care to check the switching frequency of your buck converter doesn't change depending on the load. that will change your output ripple significantly when you turn on/off different lights.
you need to be aware of the frequency of the ripples and use the appropriate types of capacitors to filter that noise band. the author of this video didn't go near enough into what to do about noise.
Is there a ripple and noise free power supply?
If the high voltage power supply (500v) how can measure is?
Use a 100/1 voltage divider
How can full wave output be double the frequency when the output is DC?
Ya I am a bit confused about how loosely he throws around frequently in dc voltage I always learned that frequently doesn’t exist in DC that’s why it’s direct current
interesting 🙂
LEARNELECTRONICS, AC ripple Water analogy, if there is no AC ripple the water flow is EVEN.
If their is AC Ripple the AC ripple makes water ripples waves in the water because does it "alter" the water flow?
Havent used my scope in so long, i feel like im neglecting it now.
+J. Clowers never neglect your scope. Lol
dont bother. use an FFT. ya shouldnt rely on a scope for this sort of work.
I don't mean to be rude, but you also should measure zero to max rms too.
Why are u using a cheap Chinese oscilloscope to do a ripple measurement?
Invalid. Faulty probing technique.
Why don't people just do this instead of replacing all their electrolytic caps or desoldering them and doing complex tests that require more equipment?
another electronics video on noise and another person using a scope. use a spectrum analyser. you're talking about a composited signal. use a spectrum analyser. you cant make out dick all details on an oscilloscope - especially when the high frequency ripples are many orders of magnitudes smaller than larger ripples. noise is a spread spectrum phenomenon
And your point is what, exactly?