Love the simple explanation. So many times people assume a certain level of knowledge which ends up confusing the beginners like me and causes us to waste hours searching for clarifications that would only have needed 1-2 more words in the original guide to explain.
@KarldorisLambley
Жыл бұрын
fantastic video. i have spent an hour or so trying to work out how to furnish an op amp with -V. this video told me everything i needed. thanks.
@baruchben-david4196
4 жыл бұрын
Thank you. You've taken the mystery out of these power supplies...
@RalphWLundvall
4 жыл бұрын
This is GOLD.
@eolhcytoos
3 жыл бұрын
Just bought an adjustable power supply with the 3 terminals. Totally lost on how to use them, now totally confident on how to use them. Clear and concise info. Thanks!
@justinle998
8 жыл бұрын
Excellent video... Keep up the great work! Ur videos are some of the best on youtube.
@fred9za
6 жыл бұрын
thanks again yet again i learn from this channel you sir are a invaluable asset to the learning enthusiast
@Tobinindustrial
8 жыл бұрын
I recently acquired some test gear and among the gear was a HP 6024A variable power supply.. I recently did a video on the gear and in that video I questioned why there was a negative and ground on the power supply. Your video explains it quiet well. Your video was most helpful to me. Thanks for sharing
@jrdubois112277
8 жыл бұрын
Another great video! Between you and Mr Carlson's Lab I feel like I am back at college, only this time I am actually learning something and enjoying it. Also I can afford better beer now.
@g0fvt
8 жыл бұрын
Handy little power supplies, handy to be able to float them so far too!
@PCLoadLetter84
5 жыл бұрын
This video is AWESOME. I have a photodetector that has a plus, minus, and ground attachment and its datasheet calls for +- 15V supply and 75 mA. This is exactly what I needed. Liked/subscribed.
@davidholman2536
8 жыл бұрын
Thank you very much Alan. I've just bought an old twin dual rail power supply by Farnell off Ebay. After watching this film I connected the jumpers up for +6 and -6 v with respect to ground. My current project - a two tone oscillator with burst mode from the RSGB Test Equipment book came to life. I'd tried making a negative voltage ladder but its output went positive under load. So a cash solution was successful. 73 David M0YDH
@toniliveinlisbon
7 жыл бұрын
Thank you very much for the demonstration on how to use ground on the power supply!
@holgerreichel7396
8 жыл бұрын
Thanks a lot for all your technically very well made videos! Super sharp HD not blurred. I enjoy watching all of them.
@mikelogix2974
8 жыл бұрын
As always, great video, I am so glad I subscribed to your channel and always look forward to new videos. The battery analogy was the best way of explaining that ubiquitous, yet misunderstood third terminal.
@els1f
8 жыл бұрын
I just bought a lab power supply for the first time (i've been needing one FOREVER). I was checking the voltages between Ground and + or -, and was certain it was broken. I would run it for 30v and see barely any movement. Then I watched this video, smacked myself in the face, and felt stupider than I've felt in a really long time :) Thanks for making this. It was extremely helpful.
@w2aew
8 жыл бұрын
I'm glad this video helped. In many applications, connecting to ground is optional. It is there for those situations when you specifically want to pin ground to a particular rail.
@dmitrykotikov6827
4 жыл бұрын
Thank you very much! Everything becomes clear after your explanation!
@chillidogkev
4 жыл бұрын
Super video that explains just what I needed to know right at the point I needed to know it. Many thanks!
@sudarshankj
4 жыл бұрын
Your videos are simply the best!
@deangreenhough3479
8 жыл бұрын
Well explained, I have never gotten to the bottom of + - voltages. Thank you for explaining the obvious.
@rualmac
2 ай бұрын
Very helpful!
@aaronbrown2587
6 жыл бұрын
Appreciate you going through the basics for the newbies :)
@yogi9631
4 жыл бұрын
thanks for upload bro !! to me, D.C was always just positive and negative. I never fully understood the Zero V in the middle !!! subscribed
@jchelm1979
8 жыл бұрын
very clear and concise
@DAVET38
8 жыл бұрын
Another nice video, Alan. Thanks.
@PeterMilanovski
6 жыл бұрын
Great... I know that this video is old but I'm glad it's here... Allot like many people here I had no idea that there was another way of doing it for different applications... I always wondered why my cheap eBay laboratory power supply had the earth terminal... I thought that it was there to be able to connect an earth strap to myself for working with sensitive stuff... But the one thing that puzzled me was why they put a jumper bridge from the negative terminal to the ground terminal.... Well now I know!!!! Now all I need is another 0-35v 10A supply to be able to make use of the split rail to be able to connect most of my amplifiers... Either that or maybe someone will post a good video on a adjustable power supply with split rails and high current ability for testing power amplifiers... Because those things in the shop's request an organ donation to be able to afford one LoL... The Astro 30 has one on his bench which is a kit that he must have built up himself but I think that it has certain current and voltage limits which would be great for Preamps and such... But I don't think that it could cope with the high current that I would need it for....
@HA7DN
5 жыл бұрын
I had no idea on this - i've always used some homebuilt supply which did not have this feature.
@nicholasmcneely245
3 жыл бұрын
Sometimes you just need a quick refresher! I subscribed and will be sure to check out more videos on your channel.
@cny02253
8 жыл бұрын
Great video Alan. I think that in today's world where low voltage at low power are so common, people may not fully appreciate the virtues of grounds, especially where there is substantial power or RF. I tend to look at things in terms of power grounds, (safety ) and signal grounds (RF, audio, data) and how I need to manage all that. These considerations were IMHO much more obvious back in the pre-solid state era. But this may be a subject for an entire video. Or two. lol! -73
@yannkitson116
8 жыл бұрын
Excellent description...
@FFFre4k
8 жыл бұрын
+Yann Kitson Judging by the ellipsis, your statement might be slightly sarcastic. If so, what exactly made the description to not be so excellent?
@yannkitson116
8 жыл бұрын
FFFre4k No I meant it, no sarcasm implied
@FFFre4k
8 жыл бұрын
Yann Kitson Oh sorry, my bad. Cheers.
@Лёха83-щ1ш
8 жыл бұрын
+Yann Kitson Brilliant, genius comment...
@tablatronix
7 жыл бұрын
cute power supplies, never saw those before.
@vladimirtorres4299
4 жыл бұрын
Your explanations are didactic. Congratulations. I will subscribe.
@FirstWizardZorander
8 жыл бұрын
Fantastic video! This is one of the best explanation on the topic of power supplies I've ever seen, and the "adjustable battery" analogy is brilliant in its simplicity. Keep doing what you're doing!
@pauldiaz4273
6 жыл бұрын
Simply the best! Thanks Alan
@TheRadioShop
8 жыл бұрын
Very nice! Thumbs up.
@jeanious2009
8 жыл бұрын
Very nice explanation, very nice video...thanks for sharing.
@Shawn_White
8 жыл бұрын
I have an Elenco Kit power supply and both the positive and negative supplies are already referenced to ground. without the need for any jumper wires.
@w2aew
8 жыл бұрын
+GalaticTG There are many supplies that are made that way. Nothing wrong with it at all. The only downside is that you can't use it when you need the output to float (stacking, etc.).
@gearstil
4 жыл бұрын
I think it could rise some problems if one tries to probe different things with the scope. If you`re not paying attention, you can put on short that part of the circuit through the scope ground.
@w2aew
4 жыл бұрын
Yes, you always have to be aware of where your ground is when using an oscilloscope.
@anurasenarathna1703
3 жыл бұрын
Very well explained. Thank you
@dean_murray
8 жыл бұрын
Hi Alan. always good to see a new video from you. watching it I was thinking it might have been good to mention about dual tracking power supplies. I'm not sure how common they are but I have one. Also was thinking worthwhile to note that (especially for non "lab" power supplies) that might be internally referenced to ground (not isolated) that there is a potential for short circuit when stacking them.
@waynegram8907
2 жыл бұрын
What type of tests can you do to test if any power supply is "Bucking"? How to Test the power supplies bucking functions ?
@mikerobinson605
8 жыл бұрын
think this was made more complex than needed, i agree with some previous comments
@w2aew
8 жыл бұрын
+mike Robinson I was just trying to be complete. I'm sorry you felt that I made it too complex.
@billwilliams6338
5 жыл бұрын
Oscilloscope ch#1 is on the output of a tube output measure the AC Peak to peak Voltage of the audio signal, Ch#2 is on the power supply output voltage. When the volume is turned up to 10 the audio P/P voltage is at its maximum and the power supply output voltage will take to collapse 10% to 20%. I'm not sure if the speakers load impedance resistance and the output transformers impedance loads down the power supply to cause this SAGGing effect of the power supply output voltage collapsing.
@gelubotezan3917
4 жыл бұрын
What if we only wire the supplies as shown in the video but not touching the ground? As I can think of it, we would get a floating ground for the circuit that would use this positive/negative supply and the circuit would work but what are the consequences?
@hubercats
4 жыл бұрын
Thanks for the nice, clear explanation. Is it important that the neutral point (between the + and - supply) be connected to earth ground? It doesn't seem necessary, at least as regards feeding, for example, a protoboard on a benchtop.
@w2aew
4 жыл бұрын
It is not super-important. In effect, it's no different from powering your protoboard from a battery.
@LiveMusicOntario
5 жыл бұрын
I like the background clutter on your bench. It makes me feel at home :) The first half of the video was informative but then for me it got "weird" when the cables were being plugged in here and there. I suppose then that those HP's are different from an old BK supply I intend to buy. #1735A. The BK manual shows that you can get both + and - outputs supplying power with reference to the third ground terminal. That's how they show it to be used for supplying a circuit that needs dual polarity, ie. op amps. It's why I want a bench power supply of this type, but your demonstration showed no voltage at + or - until one of them was strapped to the ground, time 1:20
@w2aew
5 жыл бұрын
On most lab supplies, the voltage always appears between the + and - terminals, but neither of these is tied to ground until *you* tie one of them two ground. In that sense, the + and - terminals are very much like the + and - terminal of a battery - floating, with no inherent ground connection.
@ydonl
5 жыл бұрын
Charliebrm1, it's been a while, so this may not be helpful, but... It seems like you're going through the same quandry I did recently, trying to figure out why I couldn't just get a three-terminal +/- supply for dual supply op-amp circuits. It seemed so obvious that's how it ought to work. Well, not so much! I dug around to find the manual you might be talking about; and if you're referring to what I see as figure 3D, where the various ground configurations are shown and discussed, notice the important point that the figure mentions "Grounded, not common with negative or positive polarity." In other words, the ground terminal and the supply terminals have nothing to do with each other. The positive and negative terminals are still floating, and still have the (single) supply voltage between them. The ground terminal is being used to provide a convenient ground to the device, and that's all. It's equivalent to connecting plus and minus from the power supply, and then running a separate wire from the device's ground to the wall outlet ground. To get + and - 15v with respect to ground, you'll need two supplies, or one dual (or triple) supply.
@JDDupuy
8 жыл бұрын
Nice explanation and video. Now I understand what the ground terminal on my Tektronix PWS2326 DC Power supply is for. Thanks for being a great teacher. de N0IRS
@timhnartiel
2 ай бұрын
Forgive the question, I never really got in depth with these sort of things, and I am just getting back into it now, fixing monitors and TVs etc. If you wanted, say, +15V and -15V rails with a common ground, why wouldn't you just set both supplies to 15V, connect supply 1 negative to supply 2 positive (using the connection as a "ground"), and use supply 1's positive as +15V, and supply 2's negative as the -15V rail? I am a bit wary about connecting an otherwise floating voltage to a mains ground that could become live at any time, should a serious fault occur elsewhere in the mains system. Thanks in advance 😁
@w2aew
2 ай бұрын
Either will work. Connecting the common point to mains ground will keep the voltages from floating far away from earth ground.
@MIKETEIXEIRA
8 жыл бұрын
Very good video, I have been asking myself why three and came up with the wrong answer.
@ajayrao69
8 жыл бұрын
Excellent explanation !
@maurosobreira8695
5 жыл бұрын
Try to google this kind of information and you will see how difficult it will be to find it! Nice. Thanks Alan!
@yuseffnehru8612
Жыл бұрын
May Allah bless you for the video suggestions ☺️
@AmRadPodcast
8 жыл бұрын
Love the back to basics! 73s
@surgingcircuits6955
7 жыл бұрын
Really helpful. Thx. I see my question answered below in the thisnicklldo posted thread. Cheers!
@Jnglfvr
2 жыл бұрын
The way you have both power supplies hooked up at 4:14 creates an earth reference for your circuits which may not be desirable. Why not connect the negative terminal of the upper supply to the positive terminal of the lower supply and use that as your (floating) ground reference. The upper supplies positive terminal would then be at +15 V and the negative terminal of the lower supply would then be at - 15 V both relative to a floating ground.
@w2aew
2 жыл бұрын
Yes, you certainly can do that.
@srivatsarupadhya6116
3 жыл бұрын
What is the use of a mains earth referenced power supply? It increases the risk of blowing the scope if not probed properly
@SomeGuyInSandy
4 жыл бұрын
I didn't know you could do this!
@thisnicklldo
8 жыл бұрын
Probably a dumb question, but can I take the connect the negative on the top supply directly to the positive on the bottom supply, (i.e without connecting to ground) and thereby get a mains-isolated split supply?
@jackwhite3820
8 жыл бұрын
Yes.
@w2aew
8 жыл бұрын
+Jack White As Jack said - yes you can.
@vonzigle
8 жыл бұрын
That was a good question... thanks for asking!
@ramestica123
8 жыл бұрын
+thisnicklldo same here, thanks for asking that question. After starting to watch for a second time then it also dawned on me that the video was not explicit on why using mains ground was so pervasive through it.
@w2aew
8 жыл бұрын
+Rodrigo Amestica I guess I should've made it clearer that connecting the GND is optional. In general, it is a good idea so that your supply doesn't float somewhere unexpected. But, in many, many applications, keeping the supply floating is perfectly fine.
@R0CKZ0LID
8 жыл бұрын
Very good explanation. There is one very important thing to be aware of when the supply is connected to ref. ground. Using an oscilloscope for example. The oscilloscope's probe clip is connected to ref. ground. If the device you are probing is powered with ref. to ground and by mistake connect the probe clip to any positive (+) part of the device you're testing, there is a high risk of blowing up your oscilloscope. What I basicly have as a rule of thumb is to always connect your test equipment like oscilloscopes, function generators, bench meters and so on referenced to mains ground and always power the equipment you are testing/probing with a mains-isolated supply. Edited to clarify: The power supply should be connected to mains ground. What I meant was if you power a device through mains ground output i.e. Green on most supplies. There are ofcourse exceptions in special cases. Hope this saves some scopes out there. Cheers.
@kaybhee6
2 жыл бұрын
do u know of any single box linear ps that can output plus and minus 15vdc,, instead of 2 boxes
@esnam6557
8 жыл бұрын
Very nice video thank you
@andrewferg8737
5 жыл бұрын
Thanks for another great lesson! Question: When using a CT transformer for a split supply, should the CT be connected to the earth / ground wire of the the three prong power cord plug?
@w2aew
5 жыл бұрын
Only if you need/want your common node grounded or not.
@johndooley2401
6 жыл бұрын
Thank you well put.
@Sujitth
6 жыл бұрын
Thank you very much, yes it was a mystery and not any more. but still a few doubts, I have a dual channel isolated PSU and on the Earth(GND) Terminal -mentioned Max +/-100Vdc to gnd) what will happen if the voltage goes above 100V? If I need -15V supply, I can connect my load in reverse to the + and - terminals without linking GND(Earth) to +ve terminal right? is this a correct way? and for +15 and -15 volts, I can short the CH1 -ve and CH2 +ve together to make a commin negative and take output from CH1 +ve and CH2 -ve terminal right? which use case demands a GND reference? when measured between the Earth(GND-mentioned Max +-100Vdc to gnd) and CH1&2 -ve/+ve terminals there is around 7VAC 50HZ present, what will happen to that voltage when I linked the earth(gnd) to CH +ve or -ve terminal and how much amps will flow? I am not dare enough to test it.
@w2aew
6 жыл бұрын
You run the risk of damage if either the + or - terminals are taken more than 100V away from ground. For -15V, you can simply connect your DUT "reverse", since the + terminal will be 15V above the - terminal, which is the same as saying that the - terminal is 15V below the + terminal, which is also the same as saying that there is a 15V difference between the + and - terminals. It is generally a good idea to tie in ground when you don't specifically need a floating supply. For your +15 and -15 case, I would tie CH1- to CH2+ and tie them both toe GND.
@michaelhawthorne8696
8 жыл бұрын
Thanks for the video Alan but can I ask you what is the difference between connecting the PSU's the way you did using the GND and not simply connecting the + of the lower PSU to the - of the upper and connecting your circuit between the - of the lower and the + of the upper? Like the HP supplies by the way, how do you get hold of such old equipment?
@w2aew
8 жыл бұрын
+Michael Hawthorne The only difference is that if you don't tie in the GND terminal, the supplies will not be ground referenced. In many cases, this is just fine. However, many circuits will need to be connected to other circuits/equipment that are ground referenced, so including the ground will keep the supply voltages from floating off of ground. For example, your oscilloscope is ground referenced - when you connect your scope probe's ground to your circuit, you're establishing a ground reference at your circuit. If the supply is already ground referenced, this would help to avoid a small "floating" difference between the circuit and the scope. In vast majority of cases, the small potential difference would safely and quickly go away when the scope ground was connected anyway. Just a bit of extra safety keeping the circuit and the equipment referenced to the same ground.
@RalphWLundvall
4 жыл бұрын
I found HP power supplies on eBay. I got a pair of HP 6214s - a model with lower voltage and higher amperage. I may get a third. About $40+ each.
@enojelly9452
2 жыл бұрын
I don't know if I'm being dumb, but even when not stacking I always connect my negative terminal to the earth plug unless I explicitly want the supply to be floating. I do this just because I will sooner or later likely connect the circuit to ground, and I want to avoid "surprises". Be it USB or the ground lead of an oscilloscope probe, for example. I know that especially for the probe it might be safer to not have my circuit connected to ground, because then accidentally having the ground lead where it shouldn't be won't blow it up, but that's actually part of why I'm doing it: I don't want to get used to it being okay to connect my ground lead anywhere, until one day it isn't because I also connected the circuit to ground through USB or an audio output or something.
@w2aew
2 жыл бұрын
No, you're not being dumb at all. I will keep my (-) terminal connected to ground most of the time too.
@armandine2
3 жыл бұрын
I have a number of practical electronics books which omit this helpful info - and I'm always frustrated when they give a lot of circuit examples where it is necessary prerequisite to implement them.
@AB-yu2tj
2 жыл бұрын
Thank you.
@jvon3885
2 жыл бұрын
So when stacking you are in essence adding to the longevity of each unit since you won't be pushing them so hard? In HHO applications for building a torch would this method help to not get things hot? And since they can push and pull would one be able to add one on the backside of the cell to help keep a good flow? Heat is needed but not in the supply units.
@shahafe2000
10 ай бұрын
Great! Thanks!
@espenbgh2540
8 жыл бұрын
Thanks for all your educating viedeos
@sureshlingabathina
8 жыл бұрын
Excellent
@IZ0MTW
3 жыл бұрын
Hello Sir, I need a little help please. I’m experiencing a nasty noise from my regulated 13.8 ps. It’s a linear ps. Can hear the noise in the radio up to about more than 2 MHz so I decided it’s better to have a look at what’s wrong. I understand the concept of floating terminals and so mines are. But I got a bit of a shock today touching two coax shileds. One is connected to one radio ( ft991a) powered by the ps at 13.8 so the black lead is referencing the chassis of the radio. The other shield is from the coax connected to a second radio which uses its internal switching ps (ft1000). So this latter shield is referenced to earth from the main. I was disconnecting the coaxials. After the shock I measured about 170V AC between the two after being disconnected. After further tests I can tell the external regulated supply has a potencial difference of about 140 ish Volt AC between main line and either one of those 13.8 terminals. Similarly there’s about 40 V AC between neutral and either one of the DC terminals. They are floating as you say in this video. Is this behavior normal or something is wrong with my power supply? Hopefully I’ve been clear enough in my explanation. Thank you for your answer.
@Sysshad
Жыл бұрын
Would you really need to use the GND terminal at all if trying to get +15V and -15V at the same time? Connecting anything to GND seems useless, unless you want to skip connecting the oscilloscope GND terminal when measuring something.
@indigoskywalker
6 жыл бұрын
I was looking at these psu's on ebay recently, hp made quite a range in the day... How noisy are they? Can you create a video showing the build or internals and ripple?
@w2aew
6 жыл бұрын
I've never measuring the ripple/noise - but also never felt it necessary (because they seem pretty quiet).
@jonka1
6 жыл бұрын
Why did you make the ground connection? Could you not have connected the top -ve to bottom +ve and made that the common without tying it to ground?
@w2aew
6 жыл бұрын
You can. You have the flexibility of referencing to ground the the supply, at the DUT, or somewhere else (or even float the supply).
@aa7ae
7 жыл бұрын
It seems counter intuitive to take the positive side of the power supply and connect it to the ground terminal of the other, you'd think it would short right out and have fireworks. But it's because it's isolated?
@geevnahal7926
7 ай бұрын
Can I make a circuit and add it to the output and get +1/2 output and -1/2 output with respect to ground?
@drorwald2656
8 жыл бұрын
Hello Alan. is it possible for you to make a video about Bias-T circuit ? one that can feed a Masthead LNA or a Antenna motor. I thought it can be an interesting topic for a video. Thanks for your time and effort, Dror
@w2aew
8 жыл бұрын
+Dror Wald I'll add that to my list of future topics.
@drorwald2656
8 жыл бұрын
Thanks
@Boz1211111
2 жыл бұрын
Thanks for the info! Havent thought about connecting them in series. Sadly my psu is from china and there is no spec for max float voltage, how do i know how much is safe, is there like a rule of thumb that its safe to 100v? Its wanptek dps series psu
@kevingray707
8 жыл бұрын
Another good one.
@DW7BPB
Жыл бұрын
is it safe to take the series + & - terminal as ground for a split supply? in my country a separate dedicated ground line in mains isn't a standard
@w2aew
Жыл бұрын
In most lab supplies, the voltage is generated between the + and - terminals, not between either and the ground terminal. So that won’t give you a split supply.
@power-max
8 жыл бұрын
I actually have that exact model power supply, it is really nice for small electronics work, just wish it had separate voltage and current displays! The model I have goes up to 50V though, and I think the current goes up to 600mA, although it is rated 500mA max and cannot reach the full 600mA even when shorted. It is rated for 500mA anyway so I am not worried about that.
@w2aew
8 жыл бұрын
I've also got a 15V / 1A version too.
@power-max
8 жыл бұрын
I like their small form factor a lot, they are easy to deal with. I need to find another one because constantly building up a craptacular zener diode shunt regulator to give me dual rail-like output is annoying.
@funkyironman69
8 жыл бұрын
+Power Max We have them at work too (and the older 721A). :)
@jorggradert1854
2 жыл бұрын
As you mentioned is the ground terminal typical connectet to mains ground. So i always thought that this is the terminal that i lovely would connect to my esd mat. Am i wrong to think that stacking power supplys with only two connections should do the same like stacking batteries? Maybe a little harder to find the ground wire afterwards. Did i miss the point? Is there a benefit to connect my circuit ground to mains ground maybe? Thank you.
@w2aew
2 жыл бұрын
You are correct that stacking power supplies with the two connections is the same as stacking batteries in series, assuming two things: your supplies have floating non-grounded outputs, and you don't exceed the maximum offset voltage (terminal to ground) rating for the supply. if you are going to be connecting other instrumentation that is not isolated (scope, signal generator), then you may want to tie your power supply reference rail to ground. Otherwise it is perfectly fine to just treat the two terminals of the supply like a battery.
@jorggradert1854
2 жыл бұрын
@@w2aew thank you so much, got it now.
@hexdragon_
5 жыл бұрын
Thank you very much!
@meepk633
3 жыл бұрын
Ok but why can't you skip the ground plug all together? What happens if you just do the negative-a to positive-b? Could you use either of the connected ports as ground while the unconnected ports are positive and negative?
@w2aew
3 жыл бұрын
You certainly can skip using the ground connection entirely - this is much the same as using a battery as a source. You could arbitrarily assign "ground" to either end.
@robertcalkjr.8325
8 жыл бұрын
Thanks Alan.
@eurobum2012
8 жыл бұрын
You didn't mention connecting them in parallel. Is that a good way to supply more current? Will there be issues if the voltages are slightly different?
@w2aew
8 жыл бұрын
That's because it isn't a good idea. It is not a good way to increase the current. There are some supplies that have special (rear panel) connections for running them in parallel.
@superdau
8 жыл бұрын
+Euro Bum As soon as the voltages are different (and they will be), one power supply "drives" the other. If you load the setup the one with the higher voltage will supply all the current until its internal resistance or current limit bring it down to the level of the second one at which time that one will start to provide some current as well. And don't think about trying to set both supplies to the exact same voltage. It may work for a short time, but the output voltage of these power supplies typically drifts around alot with temperature. If you need more current, get a bigger supply or get a supply that has the ability to be paralleld (I have a lab supply for example, that has dual independent outputs, but a simple switch that allows the outputs to be connected in parallel or series)
@mrjohhhnnnyyy5797
8 жыл бұрын
+superdau Exactly!
@Oldunlock
3 жыл бұрын
I just bought a pOWER SUPPLY- But I would need a separate + 12V, a separate -12V and a separate GND. Does that mean I can solve this by buying another Power supply?
@w2aew
3 жыл бұрын
yes
@astorina
3 жыл бұрын
Hello, one question , can I take the "floating" minus of first one and input it as a reference of the plus of the second one, in order to still have +15 and -15 but completly isolated from earth , as I have seen that being "connected" to earth my be a risk when measuring with a scope a circuit that would be powered up ? Thank you and much regards for your great videos. Take care.
@w2aew
3 жыл бұрын
Yes you can.
@nozefian
5 жыл бұрын
It should be noted that if you supply a circuit you are testing with mains ground (as shown here), then your oscilloscope and circuit is at risk if you accidentally connect the ground probe lead to anything other than ground (as that probes ground lead is also connected directly to mains ground). It's always safer to test a "floating" (or isolated) circuit than a mains ground connected circuit. It's explained very well here: kzitem.info/news/bejne/2Zd7sqV3qGacnoY
@billwilliams6338
5 жыл бұрын
yes I understand about what hot chassis is. When you have a 3 wire line cord and you put your current clamp on the chassis green wire, it will measure chassis leakage current. I'm not sure where this chassis leakage current is coming from. But all pieces of equipment has chassis leakage current, just put your current clamp on the green wire on your 3 wire line cord and it will measure leakage current. I thought chassis ground green wire was at zero voltage zero mA current.
@waynegram8907
3 жыл бұрын
Older power supplies circuit would use a Parallel power resistor places across the input/output pins of the regulator chip and the value of the parallel power resistor would determine how much output current the regulator and power supply would source to the circuit under test. The Parallel Power resistor is bypassing the regulator chip by sourcing more current path around the regulator chip. The regulator chip starts to self regulate the input/output current when doing this. It's very confusing how this works, can you explain how this works better?
@valentinaselektrikas
9 ай бұрын
You do not need GND connection in order to stack PSUs or to have -15V and +15 supply. So question remains why do you use ground?
@w2aew
9 ай бұрын
Tying the GND to the zero-volt reference point in your circuit helps to prevent noise coupling to (mainly common mode noise) the supplies. It is also important if your circuit to going to be connected to other circuits or equipment that is grounded.
@valentinaselektrikas
9 ай бұрын
@@w2aew Thank you I think I undetstand now.
@itrstt66
2 жыл бұрын
i dont get it why on minute 4:00 you cna take reading with polarity, i was waiting for you to put a lead the lower powersupply negative and the other lead to the upper power supply ground lead. can you elaborate more on that?
@itrstt66
2 жыл бұрын
i asked it to early, i already got it
@waynegram8907
4 жыл бұрын
Why is using one tube rectifier power supply limited to using 40uf to 50uf for the maximum capacitance value. If you use two tube rectifiers in parallel it will increase the current? and you can also use a higher value filter caps 80uf to 150uf any reasons why?
@F3rnando666
5 жыл бұрын
Excellent video! quick question? Does the current protection/limiting feature of the PSU still work when they are connected in series?. In other words, if I get 30V out of 2, 15V PSUs in series (like you did here) and I short the (30V) output, will the constant current function kick in or will I have 2 dead 15V PSUs??.. Thanks!
@w2aew
5 жыл бұрын
The current limit should still work, on properly designed power supplies.
@davidannett3322
8 жыл бұрын
Brilliant vid!
@ZlayaCo6aka
8 жыл бұрын
Alan, Do you still have the 50V and 100V supplies of the same series?
@w2aew
8 жыл бұрын
No, I never had those. I only have the two shown in the video, and the 12 or 15V version.
@billwilliams6338
4 жыл бұрын
W2AEW, guitar players are saying that their overdrive & fuzz guitar pedals that take batteries will sound different when using different types of 9volt batteries NON-Rechargeable 9 volt batteries like Alkaline, Carbon zinc, Lithium, Mercury because of the DC resistance of the 9 volt battery. A guitar players overdrive pedal will sound different if you use an Alkaline, Carbon zinc, Lithium, Mercury battery each will sound differently because of the batteries DC resistance 1.) Why does the battery DC resistance affect the sound of an amplifier pedal or fuzz pedal? 2.) Why does each 9 volt battery type Alkaline, Carbon zinc, Lithium, Mercury have a different battery DC resistance? 3.) What is a batteries DC resistance?
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