Power supply questions

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Re: Power supply questions

Postby Karlsweldt » Sun Oct 02, 2016 5:05 am

You cannot get more "out" of a power source than its design, or it can become an instant fireball.
Per Ohm's Law, 12 volts at 10 amperes is only 120 volts at 1 ampere, ignoring losses in conversion from one voltage to another.
Inverters and converters change one type of voltage to another, such as DC to AC or inverse, or reverse the voltage polarity.
Some designs can increase voltage levels up to 100x the input voltage.. such as neon sign transformers or auto ignition coils.
Motherboards and almost all other electronic gear require pure DC voltages for operation.. very few require an AC voltage. Common voltages for a computer are +3.3 volts, +5 volts, +12 volts and -12 volts.
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Re: Power supply questions

Postby LakaWaka » Sun Oct 02, 2016 1:22 pm

Karlsweldt wrote:You cannot get more "out" of a power source than its design, or it can become an instant fireball.
Per Ohm's Law, 12 volts at 10 amperes is only 120 volts at 1 ampere, ignoring losses in conversion from one voltage to another.
Inverters and converters change one type of voltage to another, such as DC to AC or inverse, or reverse the voltage polarity.
Some designs can increase voltage levels up to 100x the input voltage.. such as neon sign transformers or auto ignition coils.
Motherboards and almost all other electronic gear require pure DC voltages for operation.. very few require an AC voltage. Common voltages for a computer are +3.3 volts, +5 volts, +12 volts and -12 volts.

Yeah, that's what I figured... it doesn't make sense.
Wait, so how does it "increase" voltage levels...?
Thanks for the info on the voltages, I have read about them before. I believe CPU and Ram have lower voltages as well, I guess the mobo regulates that for the CPU? If the CPU only uses a smasll amount, what else does the CPU connector power?
I guess I will contact the company, because I do not understand how I could use a 160W converter to power a 250W power supply. They have 2 PSUs 160/250 and the converters are 80/160.... There has to be a reason for this. You mentioned that some designs could increase voltage levels, so if the voltage level was increased 2x, then you could get the required power, but I'm still wondering how that's done... I thought maybe the caps in the PSU could store enough power, but after awhile it would need to get more than 160, and then bad stuff would happen, as you mentioned above...
Thanks.
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Re: Power supply questions

Postby Karlsweldt » Sun Oct 02, 2016 3:24 pm

A transformer is the most common means of increasing or decreasing AC voltage. Every PSU has one, unless there is direct conversion to DC via diodes and capacitors. That method is known as a voltage-doubler.
A lot of utility or power poles on streets have a huge "can" near the top. That is a transformer, dropping the primary mains down from maybe 5,000 or 11,000 volts to what is needed locally. Normal residential needs are single-phase, with only one large insulator on top. For three-phase needs, there would be three large insulators on top. Common 3-phase mains are 120° out of phase to each other, and provide a more uniform power source than the single-phase setups which are 180° out of phase. Common 3-phase sources are 115/208 volt, 277 volt, 440 volt.
But still, physics controls what amount of current comes out, never more than what goes into a power supply. Ohm's Law also is at work here.
Every power supply or PSU notes on its label what each output lead has as voltage and current, and combined current as watts or amps. And also notes the input AC current needs, and what voltage range.
The transformer in a PSU is an entirely different design than normal AC power transformers. Normal transformers are designed to work with 50 to 60 Hz, while a PSU transformer works with 200 to 400 Hz. The higher the frequency, the smaller the mass of magnetic structure needed to resonate at that frequency, and transfer magnetic impulses to the other windings.
A lower frequency than intended can cause the transformer to burn up quickly.

Sorry if I am putting out too much tech info, but electricity is fascinating, and our lives would not be so without it.
Give any form of electricity great respect, but never fear it. But fear lightning, as it has other plans.
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Re: Power supply questions

Postby LakaWaka » Wed Oct 05, 2016 11:10 am

Karlsweldt wrote:A transformer is the most common means of increasing or decreasing AC voltage. Every PSU has one, unless there is direct conversion to DC via diodes and capacitors. That method is known as a voltage-doubler.
A lot of utility or power poles on streets have a huge "can" near the top. That is a transformer, dropping the primary mains down from maybe 5,000 or 11,000 volts to what is needed locally. Normal residential needs are single-phase, with only one large insulator on top. For three-phase needs, there would be three large insulators on top. Common 3-phase mains are 120° out of phase to each other, and provide a more uniform power source than the single-phase setups which are 180° out of phase. Common 3-phase sources are 115/208 volt, 277 volt, 440 volt.
But still, physics controls what amount of current comes out, never more than what goes into a power supply. Ohm's Law also is at work here.
Every power supply or PSU notes on its label what each output lead has as voltage and current, and combined current as watts or amps. And also notes the input AC current needs, and what voltage range.
The transformer in a PSU is an entirely different design than normal AC power transformers. Normal transformers are designed to work with 50 to 60 Hz, while a PSU transformer works with 200 to 400 Hz. The higher the frequency, the smaller the mass of magnetic structure needed to resonate at that frequency, and transfer magnetic impulses to the other windings.
A lower frequency than intended can cause the transformer to burn up quickly.

Sorry if I am putting out too much tech info, but electricity is fascinating, and our lives would not be so without it.
Give any form of electricity great respect, but never fear it. But fear lightning, as it has other plans.


No need to be sorry at all, I appreciate your time and information greatly, and I love learning about this stuff, because I've always wanted to get into electronics and building stuff. Sadly, a lot of it is a lot of info, and it's hard to follow in the middle of the night :).
So the transformer drops down voltage, but it's possible to increase voltage then as well? You mention that more wont go out of a PSU than comes in, but how do these transformers work then, it's a separate thing? If you get 115 volts in, but it raises to 300 volts, then how does that work? I can see how a step-down transformer would work (probably some giant capacitor that stores the extra ovoltage), but how do you gain voltage? Thanks a lot :).
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Re: Power supply questions

Postby Karlsweldt » Wed Oct 05, 2016 3:56 pm

Voltage increase or decrease with transformers is governed by the number of turns on the primary versus the secondary ratio. Current is governed by the size of the wire. The number of turns per volt could be from 1 to 1,000, depending on voltage input/output requirement. Inductance of the core and resistance of the wire are part of a complicated formula, but typically for most common AC primaries, it is about 100 turns per volt. If the primary is 100 turns per volt, the secondary is 10 turns per volt, then the output would be around 15 volts, primary 115 volts. Again, Ohm's law!
Capacitors are seldom used in a transformer power unit, unless a phase inversion is required.
For common switching power supplies (PSU type), there is no true AC source feeding the transformer. Instead, a beefy transistor or Triac turns the DC on and off quickly, in a sort of square-wave pattern. The primary capacitors store energy for between the incoming AC "flat" spots. About 20% of any true AC source has very little power.. only at its peak positive or negative range is there full motive force.
http://www.electronics-tutorials.ws/acc ... eform.html
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Re: Power supply questions

Postby LakaWaka » Thu Oct 06, 2016 9:14 am

Karlsweldt wrote:Voltage increase or decrease with transformers is governed by the number of turns on the primary versus the secondary ratio. Current is governed by the size of the wire. The number of turns per volt could be from 1 to 1,000, depending on voltage input/output requirement. Inductance of the core and resistance of the wire are part of a complicated formula, but typically for most common AC primaries, it is about 100 turns per volt. If the primary is 100 turns per volt, the secondary is 10 turns per volt, then the output would be around 15 volts, primary 115 volts. Again, Ohm's law!
Capacitors are seldom used in a transformer power unit, unless a phase inversion is required.
For common switching power supplies (PSU type), there is no true AC source feeding the transformer. Instead, a beefy transistor or Triac turns the DC on and off quickly, in a sort of square-wave pattern. The primary capacitors store energy for between the incoming AC "flat" spots. About 20% of any true AC source has very little power.. only at its peak positive or negative range is there full motive force.
http://www.electronics-tutorials.ws/acc ... eform.html


So much information. So somehow if more wires are wrapped around then Voltage will increase? I remember doing a project in shop class where we built a motorized car by wrapping wire around a thickish piece of steel I think that was maybe 2" by .5 by .5. It was connected to a battery which caused the piece of metal to spin and move the car. Cool stuff. So it's possible for the 160W PSU to power the 250W PSU enough then, or am I missing something stilll... Really cool stuff though, love electronics.
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Re: Power supply questions

Postby Karlsweldt » Thu Oct 06, 2016 3:26 pm

Going back to the link you posted about the PSU..
https://www.amazon.com/HDPLEX-Hi-Fi-DC- ... B00J3X7RU6
Note the 4th side image down, recommended is a 250 watt AC adapter.
Yet the 6th image down is of a 160 watt AC adapter connected to the 250 watt PSU?
That is 90 watts short of what is recommended! Could cause the AC adapter to overheat and self-destruct.
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Re: Power supply questions

Postby LakaWaka » Sat Oct 08, 2016 12:49 pm

Karlsweldt wrote:Going back to the link you posted about the PSU..
https://www.amazon.com/HDPLEX-Hi-Fi-DC- ... B00J3X7RU6
Note the 4th side image down, recommended is a 250 watt AC adapter.
Yet the 6th image down is of a 160 watt AC adapter connected to the 250 watt PSU?
That is 90 watts short of what is recommended! Could cause the AC adapter to overheat and self-destruct.


That's why I'm confused and wondering about how this would happen. You claim that we could increase the voltage somehow, so couldn't that work? It seems like a weird scenario though. I would LOVE to have the regular power plug, because so many people complainm about the laptop charges breaking or whatnot, plus they are pricey, and not always available.
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Re: Power supply questions

Postby Karlsweldt » Sat Oct 08, 2016 4:05 pm

Too high a voltage for any circuit can cause solid-state items to quickly burn out. Same goes for any type of motor, it can catch fire from overheated windings. Light bulbs can burn out quickly or explode. Excess high voltage can cause many problems. Capacitors can explode. Charging batteries can overheat them and cause fires or eruptions.
Voltage stabilization is a critical part of any operation, but current needs can vary. Maximum current expected plus about 20% greater will ensure a reliable and well regulated source.
With any type of portable PSU like the one indicated, go with what is recommended as the power input. If total system loading on the PSU is within the range of that 160 watt source, then acceptable.
The only exception for a specific voltage input to a device is the 'universal' type AC adapters and some electronic gear. They may be marked as "100 volts to 240 volts" and "50 Hz to 60 Hz".

Part of the Ohm's Law equations: (Conversion losses excluded.)
10 volts at 10 amps, converted to 100 volts equals only 1 amp.
100 volts at 10 amps, converted to 1,000 volts equals only 1 amp.
100 volts at 100 amps, converted to 10 volts equals 1,000 amps!
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Re: Power supply questions

Postby LakaWaka » Sun Oct 09, 2016 12:29 pm

Karlsweldt wrote:Too high a voltage for any circuit can cause solid-state items to quickly burn out. Same goes for any type of motor, it can catch fire from overheated windings. Light bulbs can burn out quickly or explode. Excess high voltage can cause many problems. Capacitors can explode. Charging batteries can overheat them and cause fires or eruptions.
Voltage stabilization is a critical part of any operation, but current needs can vary. Maximum current expected plus about 20% greater will ensure a reliable and well regulated source.
With any type of portable PSU like the one indicated, go with what is recommended as the power input. If total system loading on the PSU is within the range of that 160 watt source, then acceptable.
The only exception for a specific voltage input to a device is the 'universal' type AC adapters and some electronic gear. They may be marked as "100 volts to 240 volts" and "50 Hz to 60 Hz".

Part of the Ohm's Law equations: (Conversion losses excluded.)
10 volts at 10 amps, converted to 100 volts equals only 1 amp.
100 volts at 10 amps, converted to 1,000 volts equals only 1 amp.
100 volts at 100 amps, converted to 10 volts equals 1,000 amps!


Thanks for the information..

Yeah, it would have been nice if the PSU could use that 160 converter, but I'm not sure why they recommend it with a 250W PSU. I am going to contact them definitely, but I am 90% sure I would not use the converter with a 250 (unless they somehow can give me a good reason why I could, that somehow you would agree with, but I highly doubt that).

I did get a KillAWatt so it's time to test how much power we are talking about now. TBH hoping this KillAWatt works well, and hopefully it is below 160... Granted, I could use 2x 160... right?

GRANTED... Even with one of those 240W Dell Adapters, it stilll wouldn't FULLY work for the 250W(400W PEAK) unit.... If it goes above 240 for more than w/e amount of time it's going to not be good, so it's weird they are suggesting these adapters for their devices....... Kind of makes me worried to buy their product, but others have reported success with the HD-plex... Just not sure if the Pico would even fit in my case, but I'll have to figure it out sometime soon :P.
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