I have made two standard, three point, power supplies, 200mA each, which may be suitable for audio. One of them provides + - 15VDC and the other one provides + - 9VDC and + - 5VDC.
The first power supply is universal and can work with 120V AC RMS mains as well as 220V AC RMS and 240V AC RMS mains.
The goal has been to make low noise, low output impedance DC audio power supplies. Because standard approaches ( L7815, L7915, LM317 and LM337 ) are used, brutal force has been used to reduce the noise by the use of high value, low ESR, Japanese audio capacitors.
I do not have a scientific way to measure the noise, but, I cannot hear any even at super high gains.
I have written the projects in a document which contains the full schematics and, I hope, satisfactory explanation. Here is a link to the folder which contains the document made with OpenOffice and called Power Supplies.doc :
Power Supplies - Google Drive
Please, inform of any errors, etcetera.
The first power supply is universal and can work with 120V AC RMS mains as well as 220V AC RMS and 240V AC RMS mains.
The goal has been to make low noise, low output impedance DC audio power supplies. Because standard approaches ( L7815, L7915, LM317 and LM337 ) are used, brutal force has been used to reduce the noise by the use of high value, low ESR, Japanese audio capacitors.
I do not have a scientific way to measure the noise, but, I cannot hear any even at super high gains.
I have written the projects in a document which contains the full schematics and, I hope, satisfactory explanation. Here is a link to the folder which contains the document made with OpenOffice and called Power Supplies.doc :
Power Supplies - Google Drive
Please, inform of any errors, etcetera.
There is a mistake on a figure 3 ( transformer) - polarity of voltages (an currents) are opposite on primaries and secondaries.
There is some amount of inaccurasies, for example, here:
"As mentioned, capacitors are needed after the bridge for two reasons :
A. To ensure a DC power supply which provides a stable DC voltage value and extremely reduced ripples ( which, for a two wave rectifier ( assumed is the positive wave is 100% identical to the negative wave, except for the sign ), have a frequency of the half waves of 120Hz for 60Hz mains ( 100Hz for 50Hz mains ), double the frequency of the AC input voltage which is 60Hz or 50Hz).
B. To filter any kind of noise such as the 60Hz electromagnetic noise, other electromagnetic noise, the diode noise of the rectifier, mains spikes which may have proliferated through the transformer, transformer noise, transformer picked up electromagnetic noise, high frequency noise of cellular telephones, switching power supplies, appliances etcetera. "
- capasitors can't make voltage "stable", they just lower the ripple. Do the capasitors filter "electromagnetic noise"? I don't sure of it. And - what is "transformer noise"? And several more questions.
There is some amount of inaccurasies, for example, here:
"As mentioned, capacitors are needed after the bridge for two reasons :
A. To ensure a DC power supply which provides a stable DC voltage value and extremely reduced ripples ( which, for a two wave rectifier ( assumed is the positive wave is 100% identical to the negative wave, except for the sign ), have a frequency of the half waves of 120Hz for 60Hz mains ( 100Hz for 50Hz mains ), double the frequency of the AC input voltage which is 60Hz or 50Hz).
B. To filter any kind of noise such as the 60Hz electromagnetic noise, other electromagnetic noise, the diode noise of the rectifier, mains spikes which may have proliferated through the transformer, transformer noise, transformer picked up electromagnetic noise, high frequency noise of cellular telephones, switching power supplies, appliances etcetera. "
- capasitors can't make voltage "stable", they just lower the ripple. Do the capasitors filter "electromagnetic noise"? I don't sure of it. And - what is "transformer noise"? And several more questions.
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I don't agree with this:
"As mentioned, capacitors are needed after the bridge for two reasons :
A. To ensure a DC power supply which provides a stable DC voltage value and extremely reduced ripples ( which, for a two wave rectifier ( assumed is the positive wave is 100% identical to the negative wave, except for the sign ), have a frequency of the half waves of 120Hz for 60Hz mains ( 100Hz for 50Hz mains ), double the frequency of the AC input voltage which is 60Hz or 50Hz).
B. To filter any kind of noise such as the 60Hz electromagnetic noise, other electromagnetic noise, the diode noise of the rectifier, mains spikes which may have proliferated through the transformer, transformer noise, transformer picked up electromagnetic noise, high frequency noise of cellular telephones, switching power supplies, appliances etcetera. "
- There is some amount of inaccurasies.
"As mentioned, capacitors are needed after the bridge for two reasons :
A. To ensure a DC power supply which provides a stable DC voltage value and extremely reduced ripples ( which, for a two wave rectifier ( assumed is the positive wave is 100% identical to the negative wave, except for the sign ), have a frequency of the half waves of 120Hz for 60Hz mains ( 100Hz for 50Hz mains ), double the frequency of the AC input voltage which is 60Hz or 50Hz).
B. To filter any kind of noise such as the 60Hz electromagnetic noise, other electromagnetic noise, the diode noise of the rectifier, mains spikes which may have proliferated through the transformer, transformer noise, transformer picked up electromagnetic noise, high frequency noise of cellular telephones, switching power supplies, appliances etcetera. "
- There is some amount of inaccurasies.
In regards to Figure 3 : there are some rules of the thumb and fist fingers of the left hand, etcetera, which would help find out the polarity. This is not the point. The pint is : transformers, as well as coils, are provided by the manufacturer with a star or a dot mark on the primary and the secondary. The polarity, referenced to the star or the dot is the same for the primary and the secondary. Thus, when current enters the star of the primary, a current will exit the star of the secondary. With voltages : when the star of the primary have a positive voltage in regards to the non star point of the primary, the star of the secondary will have a positive voltage in regards to the non star point of the secondary. Thus the primary and the secondary have the same polarity between the star and the non star of each.
Here is more information : Transformer - Wikipedia
Here is more information : Transformer - Wikipedia
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In regards to the capacitors : Capacitors do make voltage stable. To reduce the ripples means exactly this : to make the voltage more stable, closer to a single DC value without any AC movements, such as ripple. Also, ideal capacitors with infinite values make the DC voltage without any ripples. Thus, capacitors make the DC voltage stable, the question is what the level of stability is.
Transformer coils ( other components, such as high value resistors not connected to low impedance, too ) act as antennas and get any electromagnetic noise around, such as appliances, radio, TV, cell phones, etcetera. All this is AC. Thus, a low ESR capacitor with will filter all these.
Transformer noise : when the transformer electromagnetic field circles through the core, there are all kind of imperfections which can be considered micro or nano coils which would make noise. The same applies to the copper of the coil as well as not evenly wound coil, etcetera. This is much lower than the electromagnetic noise from the outside and can be ignored.
Transformer coils ( other components, such as high value resistors not connected to low impedance, too ) act as antennas and get any electromagnetic noise around, such as appliances, radio, TV, cell phones, etcetera. All this is AC. Thus, a low ESR capacitor with will filter all these.
Transformer noise : when the transformer electromagnetic field circles through the core, there are all kind of imperfections which can be considered micro or nano coils which would make noise. The same applies to the copper of the coil as well as not evenly wound coil, etcetera. This is much lower than the electromagnetic noise from the outside and can be ignored.
I want to say this thing: I know about dots on windings, whuch mean "phase" ("in phase", "out of phase"). And I know voltage "polarity" - it is always opposite on primaries and secondaries.
Marks for polarity is "+" and "-", and mark for "phase" is "dot" or "star" (usually).
As you know, idea "polarity" and "phase" - is different. So, I want you to chose right marks for you idea. (You mean "phase" - mark have to be "dot" or "star").
I don't agree with you. There are two different functions: stabilization (regulation) and filtering. They are different. Your logic is wrong. When we charge (ideal or not) capasitor the voltage will raise. When we discharge it - the voltage will fall. It cant be "stable" without some stabilizing device (regulator).
If capasitors make voltage stable, then why we need regulators as LM317/7812, ets.?
Again, words are not important. What is important is the two stars must be in the same direction. Then, when the primary is + -, the secondary is + - and vice versa.
In your terms, the polarity and the phase are the same. Phase and polarity are two terms for the same thing. When the polarities are the same, the phase is the same and vice versa. I. E. Transformer can only negate or repeat. Cannot jump waves.
Again, capacitor do make voltage stable as the voltage is stays the same, without ripples, when the capacitors are big. Voltage regulators are not needed. They can only be used not to make the voltage stable, as the capacitors have already done so, but, to make the voltage even more stable. Yet, the first stabilization comes from the capacitors. In other words, capacitors can be used without regulators for stabilization. Regulators without capacitors, cannot.
I think I have clearly explained this over two replies.
Noise reduction is a better way to say noise filtration. Filtration also means ripple filtration. Thus, filtration is not good to be used when the two tasks are separate. A better way is to say noise elimination for ideal capacitors.
I think, I have clearly explained this in two replies too.
I am sorry but I have spent a long period to answer. Please, in case you are interested in words, can you find someone else to discuss words, please.
Please, also note, I do not use terms as term usage is all wrong. Please, find other people to discuss terms too.
I am only interested in logic and reality not in terms. As originally stated, any errors, please inform. The explanations have been clearly made and they are clearer because terms have not been used.
Perhaps the problem is that you are not using the standard terms. The mains supply here is very stable at 50Hz 234.6V. Currents don't fly, they flow and they don't make decisions on where they go.
You would get more understanding of how things work if you used a simulator. Your explanation of the current path of figure 6 is incorrect.
You would get more understanding of how things work if you used a simulator. Your explanation of the current path of figure 6 is incorrect.
Mains is neither stable nor accurate anywhere in the world.
Terms create problems and must not exist at all.
I HAVE EXPLAINED EXTREMELY WELL WHAT I WANTED TO SAY. The main point was to make a good explanation as everything else is elementary.
Transformers have entry points of their coils. When current enters the primary from the entry point, the current FLIES THROUGH THE Wire from entry to exit and, makes a voltage more positive at the entry point than the exit. The current makes an electromagnetic field which also FLIES through the transformer core. This field makes a current in the secondary which exits the secondary through the entry point and continues through the load to enter the secondary through the exit point of the secondary. This may mislead the reader. The current exits through the entry door and enters through the exit door. Thus, the entry door has a more positive potential then the exit door because the current makes this voltage over the load.
The word fly is better than flow because of the higher speed, but, yes, flow can be used too because the water flows.
I will check Schematics 6 and inform you whether I have found an error.
Again, please, find other people to play word games. I cannot spend even minutes to respond to such messages.
Had a quick look at the explanation of figure 6 which is the most important and the longest. Cannot read the whole. Did not find any mistake. In case you can point the mistake EXACTLY, I can have a look. But I am not to be disturbed just because someone thinks there is a mistake.
As everyone, whe the current flies the current makes decisions. The current DECIDES not to enter a reverse diode because, to go through is either impossible or difficult. Just the same as a driver decides not to enter a one way street in an opposite direction.
Again, find someone else to play words with.
Also, words, such as current flies, decides to go here and there, are not only BETTER for explanations but are very well used because people need to use these and DO NOT NEED TO USE TERMS because, to use terms is wrong. People do not use terms in their normal environment, they use explanation because this is correct.
Hi Steven,
If I may, I know you will shoot me down, but you did ask for ''Please, inform of any errors, etcetera.'' in your initial post.
Many many too many words. Very difficult to read and take in what you might be trying to say. It reads like lots of poor google translations and misunderstandings of language.
54 pages, please who will read it, its a very simple power supply. You lost me on page 3...
Lots of errors in spelling and terminology (fly/flow, Gretz/Graetz, no/now, etc.). If you want others to read it you have to use the correct words and terms that the majority of us mere mortals understand.
Some things you do not understand, sorry.
One example is, you say ''DC currents do NOT induce electromagnetic fields as they do NOT move! In electricity, movement can be made by movement only''.
Wind a few turns of wire round a 6 inch nail and connect it to a battery. Bet the nail becomes a magnet.
It is also incorrect that ''a transformer will only work on AC''. The ones you have only work on AC, but a transformer will work on any changing magnetic field AC or Pulsed DC etc. - think how a SMPS works.
I will leave it there, sorry again, lots of work I'm sure, but please do not ask for input and then argue against anyone who dares to offer help.
Alan
If I may, I know you will shoot me down, but you did ask for ''Please, inform of any errors, etcetera.'' in your initial post.
Many many too many words. Very difficult to read and take in what you might be trying to say. It reads like lots of poor google translations and misunderstandings of language.
54 pages, please who will read it, its a very simple power supply. You lost me on page 3...
Lots of errors in spelling and terminology (fly/flow, Gretz/Graetz, no/now, etc.). If you want others to read it you have to use the correct words and terms that the majority of us mere mortals understand.
Some things you do not understand, sorry.
One example is, you say ''DC currents do NOT induce electromagnetic fields as they do NOT move! In electricity, movement can be made by movement only''.
Wind a few turns of wire round a 6 inch nail and connect it to a battery. Bet the nail becomes a magnet.
It is also incorrect that ''a transformer will only work on AC''. The ones you have only work on AC, but a transformer will work on any changing magnetic field AC or Pulsed DC etc. - think how a SMPS works.
I will leave it there, sorry again, lots of work I'm sure, but please do not ask for input and then argue against anyone who dares to offer help.
Alan
I don't argue and do not shoot.
Spelling is not important and is obvious. Of course, better to be correct.
I only use human language as explained.
Transformers cannot transform with DC. Pulse modulation is AC.
DC can make a magnet which has only one direction which means DC. The electromagnetic field cannot be converted into electricity.
AC is movement of electricity. This movement can only be made by another movement. Thus, a moving electromagnetic field is necessary. The nail field does not move. The nail moves not the field.
Should have explained this better but this is not a subject to the publication. Good to mention.
Except for the words, your post is the best so far. Not only I don't shoot but I thank you for this.
Spelling is not important and is obvious. Of course, better to be correct.
I only use human language as explained.
Transformers cannot transform with DC. Pulse modulation is AC.
DC can make a magnet which has only one direction which means DC. The electromagnetic field cannot be converted into electricity.
AC is movement of electricity. This movement can only be made by another movement. Thus, a moving electromagnetic field is necessary. The nail field does not move. The nail moves not the field.
Should have explained this better but this is not a subject to the publication. Good to mention.
Except for the words, your post is the best so far. Not only I don't shoot but I thank you for this.
Movement
As mentioned, I did not explain movement in electricity and electromagnetism as this was not a subject to the publication but, rather, a lyrical diversion.
I have tried to do so in this post. Be warned, the explanation is subject of Physics and neither electrical nor electronics. I do not pretend to have explained the subject to the same clarity level as other explanations and, frankly, this has not been the intention.
The topic is very interesting but is a side topic. Just be warned : to understand this topic is very difficult. More like philosophy than real science.
See the attachment.
As mentioned, I did not explain movement in electricity and electromagnetism as this was not a subject to the publication but, rather, a lyrical diversion.
I have tried to do so in this post. Be warned, the explanation is subject of Physics and neither electrical nor electronics. I do not pretend to have explained the subject to the same clarity level as other explanations and, frankly, this has not been the intention.
The topic is very interesting but is a side topic. Just be warned : to understand this topic is very difficult. More like philosophy than real science.
See the attachment.
I also want to mention safety.
There are two main points in safety :
1. Any piece of metal ( the enclosure too ) which may be touched by a person must be well grounded. This is because, in case of a problem ( such as a wire coming loose ) after which a wire may touch this piece of metal. When grounded, the person will only touch ground, regardless of what the loose wire touches. There may be sparks but the ground potential cannot be changed because the Earth capacitance is huge and this is where the current would go without changing the Earth's potential.
2. Ground must not touch neutral anywhere in the device. ( Obviously, ground must not touch life too. )
The devices are in Nylon covered Aluminium enclosures connected to the ground of the mains. The toroidal transformer is much safer than the nontoroidal transformers and the probability of any wire to burn and or come loose is extremely low. Even then, the enclosures are well grounded anyways.
Ground does not touch neutral anywhere in the device as per safety. Ground is connected to the chassis ( the enclosure ) with a thick wire. On the top of everything, the enclosure is covered with a nylon.
HERE IS WHAT HAPPENS OUSIDE the devices AROUND THE HOUSE :
Ground is connected to neutral OUTSIDE of the device in ONE POINT for the whole house / apartment only. Some people say there may be a few volts difference between them because of the resistance of the wires around the house OUTSIDE, although the wires are rather thick and as per the standard. No current must be sufficient to cause any difference. Regardless, safety says neutral and ground must not be connected also because their common point may break and, then, the device is the place where they would meet which is not nice. The internet, however, gives many different cases.
A much better safety approach is to use plastic enclosure and nylon bolts, washers and nuts. This, however, may not be possible, because of the electromagnetic noise, which is huge. Thus, the safest possible approach may be to use toroidal transformers. This is not mandated by the standard but is a good idea. Not only the toroidal transformers have lower noise but a higher safety too. The safest toroidal transformers are these made and approved for medical purposes. They are, probably, also sold to the general public. They are supposed to be of lowest noise too.
There are two main points in safety :
1. Any piece of metal ( the enclosure too ) which may be touched by a person must be well grounded. This is because, in case of a problem ( such as a wire coming loose ) after which a wire may touch this piece of metal. When grounded, the person will only touch ground, regardless of what the loose wire touches. There may be sparks but the ground potential cannot be changed because the Earth capacitance is huge and this is where the current would go without changing the Earth's potential.
2. Ground must not touch neutral anywhere in the device. ( Obviously, ground must not touch life too. )
The devices are in Nylon covered Aluminium enclosures connected to the ground of the mains. The toroidal transformer is much safer than the nontoroidal transformers and the probability of any wire to burn and or come loose is extremely low. Even then, the enclosures are well grounded anyways.
Ground does not touch neutral anywhere in the device as per safety. Ground is connected to the chassis ( the enclosure ) with a thick wire. On the top of everything, the enclosure is covered with a nylon.
HERE IS WHAT HAPPENS OUSIDE the devices AROUND THE HOUSE :
Ground is connected to neutral OUTSIDE of the device in ONE POINT for the whole house / apartment only. Some people say there may be a few volts difference between them because of the resistance of the wires around the house OUTSIDE, although the wires are rather thick and as per the standard. No current must be sufficient to cause any difference. Regardless, safety says neutral and ground must not be connected also because their common point may break and, then, the device is the place where they would meet which is not nice. The internet, however, gives many different cases.
A much better safety approach is to use plastic enclosure and nylon bolts, washers and nuts. This, however, may not be possible, because of the electromagnetic noise, which is huge. Thus, the safest possible approach may be to use toroidal transformers. This is not mandated by the standard but is a good idea. Not only the toroidal transformers have lower noise but a higher safety too. The safest toroidal transformers are these made and approved for medical purposes. They are, probably, also sold to the general public. They are supposed to be of lowest noise too.
A document, called Errata.doc has been published here : Errata - Google Drive
The document correct errors I may have made in various projects I have worked on.
The document is to be updated.
Please, report all errors and problems.
The document correct errors I may have made in various projects I have worked on.
The document is to be updated.
Please, report all errors and problems.
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