Wall Wart PS/Filter = Caps too big?
ezkcdude: " ... the png, it is drawn exactly to scale. If you already have a supply of some of these parts, can you just see if they fit the current board, in terms of pitch, lead diameters, body outlines, etc? ..."
It is quite common practice to have very large capacitors mounted "off board" and connect them to the PCB with (in this case) #16 to #18 AWG wire, soldered to taste directly to the existing solder pads on your PCB design without changes.
ezkcdude: " ... the png, it is drawn exactly to scale. If you already have a supply of some of these parts, can you just see if they fit the current board, in terms of pitch, lead diameters, body outlines, etc? ..."
It is quite common practice to have very large capacitors mounted "off board" and connect them to the PCB with (in this case) #16 to #18 AWG wire, soldered to taste directly to the existing solder pads on your PCB design without changes.
I agree. I think 4700 was overkill. I suppose I won't know until I actually test the board. Like I said before, for the caps, the part sizes at 100V will probably be fine, if we lower the capacitance. I think I should just get the board made, and try out several different smoothing caps. With my scope (Tek 465B), I should be able to make out the amount of ripple, but I think it will be hard for me to "see" the differences that the components elsewhere have on high frequency noise. Am I right?
As for the offboard caps, I've seen that. Personally, I'm not too keen on it, because I think you have to worry about the mechanical connection, but obviously, it's been done. Well, I guess what you're saying then, is that if people want to mod the board with gigantic caps, it could be done regardless of the final board size. That's a good way to think about it, I suppose.
As for the offboard caps, I've seen that. Personally, I'm not too keen on it, because I think you have to worry about the mechanical connection, but obviously, it's been done. Well, I guess what you're saying then, is that if people want to mod the board with gigantic caps, it could be done regardless of the final board size. That's a good way to think about it, I suppose.
Design copied from rich00boy ?? Oh, No !!!
richie00boy" " ... copied both my schematic and PCB in pretty much every way, so I find it slightly cheeky you ignore my boards when discussing commercial applications Granted the circuit is quite generic, but still I hope you can see my point ..."
Oh, my ... Sorry about that. I have not paid too much attention to all the different references to your circuit designs.
Please understand that your work is not under appreciated ... http://www.diyaudio.com/forums/attachment.php?s=&postid=955261&stamp=1152158847 ... etc., etc. is probably exactly the same as your workup ... so even with changes to values and specs of components, your pictorials / circuits / boards are probably worthy of mention at least ... I'll be the first to stand up and cheer = Thanks for all the work.
If you want Koo Doos when it comes time to publish, print, post the html code, etc. et al ... we will certainly at least mention your previous work ... and if we ever make more than a few bucks on this (unlikely) then I owe you dinner at a CES show ... (I have to be careful here, as knowing those guys at National, they may want drinks around as well!)
My very first job as an electronics technician was to build a better power supply than the bosses ... I failed and was fired (a good thing it turns out) ... so I made it my business to learn about AC to DC and DC to DC conversion, power supply design ...
richie00boy" " ... copied both my schematic and PCB in pretty much every way, so I find it slightly cheeky you ignore my boards when discussing commercial applications Granted the circuit is quite generic, but still I hope you can see my point ..."
Oh, my ... Sorry about that. I have not paid too much attention to all the different references to your circuit designs.
Please understand that your work is not under appreciated ... http://www.diyaudio.com/forums/attachment.php?s=&postid=955261&stamp=1152158847 ... etc., etc. is probably exactly the same as your workup ... so even with changes to values and specs of components, your pictorials / circuits / boards are probably worthy of mention at least ... I'll be the first to stand up and cheer = Thanks for all the work.
If you want Koo Doos when it comes time to publish, print, post the html code, etc. et al ... we will certainly at least mention your previous work ... and if we ever make more than a few bucks on this (unlikely) then I owe you dinner at a CES show ... (I have to be careful here, as knowing those guys at National, they may want drinks around as well!)
My very first job as an electronics technician was to build a better power supply than the bosses ... I failed and was fired (a good thing it turns out) ... so I made it my business to learn about AC to DC and DC to DC conversion, power supply design ...
Wall wart filter ripples on 'scope
ezkcdude: " ... With my scope (Tek 465B), I should be able to make out the amount of ripple, but I think it will be hard for me to "see" the differences that the components elsewhere have on high frequency noise. ..."
Yes = correct. Ripples on the 'scope can occure all over the place ... that's why I keep mentioning coils and inductors as needed ...
Pure sign wave /\/ ripples become \/\ when passing through a coil and depending on the ripple frequencies v. reactance (& reluctance [in Henrys]) can actually be made to cancel out ... so everything down stream works less hard = increases in efficiencies = better noise rejection.
"All of the worlds problems can be resolved by fixng the impedence mismatch ..." - Bob Porter / Mad Scientist.
ezkcdude: " ... With my scope (Tek 465B), I should be able to make out the amount of ripple, but I think it will be hard for me to "see" the differences that the components elsewhere have on high frequency noise. ..."
Yes = correct. Ripples on the 'scope can occure all over the place ... that's why I keep mentioning coils and inductors as needed ...
Pure sign wave /\/ ripples become \/\ when passing through a coil and depending on the ripple frequencies v. reactance (& reluctance [in Henrys]) can actually be made to cancel out ... so everything down stream works less hard = increases in efficiencies = better noise rejection.
"All of the worlds problems can be resolved by fixng the impedence mismatch ..." - Bob Porter / Mad Scientist.
cap sizes? ... more
ezkcdude: " ... I did some quick checking. With the caps, if we go to 50V rating, then we should lower the capacitance to 3300uF, and if we use 100V, then the capacitance is 1000uF for the same body outline size. This is just to give an idea. It looks like we may be safe going to the higher voltages, but may have to give up a little in terms of capacitance. ..."
It could also be possible to decrease C1A, C1B, C2A, C2B and increase C5 and C8 accordingly and produce almost identical results on your 'scope.
Overall filter capacity is not actually "determined" by the chip regulators, but increasing capacitance at the output makes it easier for the chip regulators to do their work.
... and if coils are used in place of or in addition to R1 & R2, then capacitor sizes across the bridge can be reduced further ... (these coil inductor work exactly like the coils in a crossover network = the L/C time constant increases with L and decreases with C for a given frequency, be it a noise frequency or an audio frequency at a "roll off" knee.)
ezkcdude: " ... I did some quick checking. With the caps, if we go to 50V rating, then we should lower the capacitance to 3300uF, and if we use 100V, then the capacitance is 1000uF for the same body outline size. This is just to give an idea. It looks like we may be safe going to the higher voltages, but may have to give up a little in terms of capacitance. ..."
It could also be possible to decrease C1A, C1B, C2A, C2B and increase C5 and C8 accordingly and produce almost identical results on your 'scope.
Overall filter capacity is not actually "determined" by the chip regulators, but increasing capacitance at the output makes it easier for the chip regulators to do their work.
... and if coils are used in place of or in addition to R1 & R2, then capacitor sizes across the bridge can be reduced further ... (these coil inductor work exactly like the coils in a crossover network = the L/C time constant increases with L and decreases with C for a given frequency, be it a noise frequency or an audio frequency at a "roll off" knee.)
I think my earlier concerns about cap sizes may have been a little too hysterical. The body outline currently drawn will accept the following Nippon SMG caps (and I'm assuming it will be similar with other brands):
25 V - 12,000 uF
35 V - 6,800
50 V - 4,700
100 V - 1200
That should be plenty capacitance, even if one chooses to go up to the 100 V rating. I think I will go with the 50 V rating, but maybe use 2200 or 3300 uF. FastEddy, I guess I'm about ready to order the board. If your interested in getting one for yourself, send me a PM.
25 V - 12,000 uF
35 V - 6,800
50 V - 4,700
100 V - 1200
That should be plenty capacitance, even if one chooses to go up to the 100 V rating. I think I will go with the 50 V rating, but maybe use 2200 or 3300 uF. FastEddy, I guess I'm about ready to order the board. If your interested in getting one for yourself, send me a PM.
So, would it be possible to simply replace one or more of the resistors (R1 or R2) with a coil without changing the design? You can have resistors and inductors in parallel there? If so, that would be cool. And what value inductor would be appropriate?
ready for PCB boards?
ezkcdude: " ... I guess I'm about ready to order the board. If your interested in getting one for yourself, send me a PM. ..."
I have not had time to thoroughly review the PCB layout ... but from what I remember = no problems.
ezkcdude: " ... I guess I'm about ready to order the board. If your interested in getting one for yourself, send me a PM. ..."
I have not had time to thoroughly review the PCB layout ... but from what I remember = no problems.
wall wart filter / PS with inductors?
ezkcdude: " ... would it be possible to simply replace one or more of the resistors (R1 or R2) with a coil without changing the design? ..."
Actually, yes ... keeping in mind that paralleling a resistor and a coil lets AC through to the limits of the L/C time constant, but a coil lets DC through without significant resistance, so that the resistance of the paralleled resistor is negated = not applicable. In otherwosrd, coil inductors of healthy wire sizes don't restrict DC power at all, but resistors do ... so having a resistro R1 and a coil at R1 = almost no resistance at all to DC = arguably a good thing, except for the "wasted" resistor.
It gets complicated from here on
... suffice to say that a couple of coils of different values substituted at R1 and R2 actually produce a broad range of frequency filtering and "hum bucking" feedback reactance ... to further complicate this ... the "black art" trick is to use an additional coil on the ground bus between the load and G on the PCB. This then allows further reduction in capacitor capacity (size) , thus allowing an increase in capacitor voltage rating ... tweaking and tweaking until capacitor sizes become cheap and PBC real estate becomes managable.
References: Maxwell's Equations and anything Nikola Tesla ever wrote on electromagnetic induction, then consult the ARRL Handbook (any issue from 1965 on) ... 
ezkcdude: " ... would it be possible to simply replace one or more of the resistors (R1 or R2) with a coil without changing the design? ..."
Actually, yes ... keeping in mind that paralleling a resistor and a coil lets AC through to the limits of the L/C time constant, but a coil lets DC through without significant resistance, so that the resistance of the paralleled resistor is negated = not applicable. In otherwosrd, coil inductors of healthy wire sizes don't restrict DC power at all, but resistors do ... so having a resistro R1 and a coil at R1 = almost no resistance at all to DC = arguably a good thing, except for the "wasted" resistor.
It gets complicated from here on
... suffice to say that a couple of coils of different values substituted at R1 and R2 actually produce a broad range of frequency filtering and "hum bucking" feedback reactance ... to further complicate this ... the "black art" trick is to use an additional coil on the ground bus between the load and G on the PCB. This then allows further reduction in capacitor capacity (size) , thus allowing an increase in capacitor voltage rating ... tweaking and tweaking until capacitor sizes become cheap and PBC real estate becomes managable. References: Maxwell's Equations and anything Nikola Tesla ever wrote on electromagnetic induction, then consult the ARRL Handbook (any issue from 1965 on) ...
There would be no point using 100V caps as you would never put anything like that much voltage on the board. For 100% reliable operation the max voltage each regulator input should see is about 40 volts.
I'm not trying to clamour for attention 🙂 But it would be nice and appreciated if you could provide links to my website somewhere. www.readresearch.co.uk
Good luck with your projects, both of you.
I'm not trying to clamour for attention 🙂 But it would be nice and appreciated if you could provide links to my website somewhere. www.readresearch.co.uk
Good luck with your projects, both of you.
No need for high voltage caps?
richie00boy: " ... There would be no point using 100V caps as you would never put anything like that much voltage on the board. For 100% reliable operation the max voltage each regulator input should see is about 40 volts. ... "
Yes, absolutely ccorrect. Using a 30 VAC wall wart or transformer, the peak to peak voltage is about 52 volts ... but if someone accedentally plugs that 120 VAC primary / 30 VAC secondary into an outlet in Europe ... oops, grab that fire extstingisher ... secondary voltage goes to 104 VAC or more
Anyway, there are always opportunities for a screwup like me to do the wrong thing and cook the electronic goose.
richie00boy: " ... There would be no point using 100V caps as you would never put anything like that much voltage on the board. For 100% reliable operation the max voltage each regulator input should see is about 40 volts. ... "
Yes, absolutely ccorrect. Using a 30 VAC wall wart or transformer, the peak to peak voltage is about 52 volts ... but if someone accedentally plugs that 120 VAC primary / 30 VAC secondary into an outlet in Europe ... oops, grab that fire extstingisher ... secondary voltage goes to 104 VAC or more
Anyway, there are always opportunities for a screwup like me to do the wrong thing and cook the electronic goose.
I certainly will, once I have actually built the thing. I think I will dedicate a page on my website to my DIY projects. That ought to bring you at least 2-3 visitors/year 😉.
Web links? already? ...
How about this: http://3dotaudio.com ... any page, middle of the lower area. 😀
How about this: http://3dotaudio.com ... any page, middle of the lower area. 😀
more
O.k., did some more heavy lifting...
See post #74 for links:
http://www.diyaudio.com/forums/showthread.php?postid=955536#post955536
1. Fattened traces near regs
2. Changed body outlines of smoothing caps, regulator caps, and diodes to be more uniform and to better match materials list.
3. Spaced the wire connectors (10 mm) and re-sized them (18 AWG) so that terminal blocks can potentially be used. I need to order some, and check this.
4. Added higher quality (higher rated) components to materials list (in italics)
Now, we're getting down to brass tacks. I'm going to order up some parts, make sure they fit, and then once that's done, order some boards.
O.k., did some more heavy lifting...
See post #74 for links:
http://www.diyaudio.com/forums/showthread.php?postid=955536#post955536
1. Fattened traces near regs
2. Changed body outlines of smoothing caps, regulator caps, and diodes to be more uniform and to better match materials list.
3. Spaced the wire connectors (10 mm) and re-sized them (18 AWG) so that terminal blocks can potentially be used. I need to order some, and check this.
4. Added higher quality (higher rated) components to materials list (in italics)
Now, we're getting down to brass tacks. I'm going to order up some parts, make sure they fit, and then once that's done, order some boards.
one way to do it ...
see http://3dotaudio.com/doodles.html ... a doodled up version of ezkcdude's PCB layout with more copper left behind.
The idea would be to save expenses (costs) in large production, but probably is not needed for short runs. (Speeds & feeds in the tank or on the mill be about 1/2)
see http://3dotaudio.com/doodles.html ... a doodled up version of ezkcdude's PCB layout with more copper left behind.
The idea would be to save expenses (costs) in large production, but probably is not needed for short runs. (Speeds & feeds in the tank or on the mill be about 1/2)
Yeah, I thought about filling the board like that. Is it a good idea? My understanding is that it could lead to problems with the board warping. Maybe copper could be left on the component side to balance this out? Would that increase or decrease noise? I'm happy to make these changes. Also, I'm going to fiddle around with adding some protection diodes for the regs. There may be room for some N4001's.
Board warping??
I suppose it could if it gets hot enough ... but I have not seen it happen normally.
Best reason for leaving copper on the board is costs savings in manufacturing = reduced speeds and feeds ... second best is environmental concerns = less copper & plastic in the trash ... but it is possible do do really neat things with the extra copper real estate ... like write the component part numbers in the copper, etched or milled ... R1A R1B R1C here > ... and thus eliminate the silk screening altogether >>> 😀
And another thing: to give an idea of how effective the extra copper is in shielding ... note that virtually all WiFi and GPS antennas in handheld devices are now done in copper on the PCB board = same as with RFID tags ... and if antennas work, so do well designed shields.😉 😎
I suppose it could if it gets hot enough ... but I have not seen it happen normally.
Best reason for leaving copper on the board is costs savings in manufacturing = reduced speeds and feeds ... second best is environmental concerns = less copper & plastic in the trash ... but it is possible do do really neat things with the extra copper real estate ... like write the component part numbers in the copper, etched or milled ... R1A R1B R1C here > ... and thus eliminate the silk screening altogether >>> 😀
And another thing: to give an idea of how effective the extra copper is in shielding ... note that virtually all WiFi and GPS antennas in handheld devices are now done in copper on the PCB board = same as with RFID tags ... and if antennas work, so do well designed shields.😉
😎 O.k. but I don't think you answered my question. Should I leave copper planes on the component side?
So, here I filled the entire bottom layer with the copper ground plane. Will this actually perform better? If so, it seems a no-brainer to keep it.
Also, I've added the protection diodes (D3-D6), which took some jostling about.
Also, I've added the protection diodes (D3-D6), which took some jostling about.
In this instance a copper filled area (normally you would connect it to 0V to gain a ground plane) would not hurt. In sensitive circuits it can increase capacitance to ground which can result in problems, but you should be fine here.
As has been said it's a more environmentally friendly way to do it, which I like 🙂
As has been said it's a more environmentally friendly way to do it, which I like 🙂
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