If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

A 5v with enough amps for your required draw.

5v. need to look at current draw though.

Boris said:

5v. need to look at current draw though.

okey dokey

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

You could only use a 10v supply if both appliances were identical draw, and then you would have to run them in series.

so 5v and add the two Amps together to get the required current.

Stealth said:

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

You could only use a 10v supply if both appliances were identical draw, and then you would have to run them in series.

I guess that is one option but then I’d still have to look at the other

Boris said:

so 5v and add the two Amps together to get the required current.

remarkably my maths just covers adding two items together ;)

Riff-in-Thyme said:

Stealth said:

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

You could only use a 10v supply if both appliances were identical draw, and then you would have to run them in series.

I guess that is one option but then I’d still have to look at the other

It’s not really an option because it also assumes that the load is passive, which is unlikely.

KJW said:

Riff-in-Thyme said:

Stealth said:

You could only use a 10v supply if both appliances were identical draw, and then you would have to run them in series.

I guess that is one option but then I’d still have to look at the other

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Riff-in-Thyme said:

KJW said:

Riff-in-Thyme said:

I guess that is one option but then I’d still have to look at the other

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Then you need a 5 v supply, and possibly a regulated 5v supply.

Stealth said:

Riff-in-Thyme said:

KJW said:

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Then you need a 5 v supply, and possibly a regulated 5v supply.

it’ll be a jaycar raid

Stealth said:

Riff-in-Thyme said:

KJW said:

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Then you need a 5 v supply, and possibly a regulated 5v supply.

‘Or’ not ‘and’

Riff-in-Thyme said:

KJW said:

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Then no. That load would be active (ie transistors).

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

a 5V adapter that can provide enough current to power the two devices

eg

each 5V appliance consumes 1A

therefore you need an adaptor that can provide 5V 2A

wookiemeister said:

Riff-in-Thyme said:

If I wanted to run two 5v appliances off one adapter would I use a 5v apater or a 10-12v?

a 5V adapter that can provide enough current to power the two devices

eg

each 5V appliance consumes 1A

therefore you need an adaptor that can provide 5V 2A

:)

you’ll find that most adaptors will have some kind of regulating circuit built into them

the next thing you should be thinking about how you are going to supply two devices from one power source

voltage is only a measure of electrical pressure

current is a measure of electrons flowing

a 5V device is designed to only have a certain amount of electrical pressure feeding it ie 5V

wookiemeister said:

voltage is only a measure of electrical pressure

current is a measure of electrons flowing

a 5V device is designed to only have a certain amount of electrical pressure feeding it ie 5V

I’ve been wookstructed

wookiemeister said:

the next thing you should be thinking about how you are going to supply two devices from one power source

Personally, I’d use wires.

sibeen said:

wookiemeister said:

the next thing you should be thinking about how you are going to supply two devices from one power source

Personally, I’d use wires.

Old fart. It’s all wireless these days…

in practical terms

use two 5V adapators

its going to get too messy otherwise

plus if one adaptor flakes out you’ll still have one device that works

sibeen said:

wookiemeister said:

the next thing you should be thinking about how you are going to supply two devices from one power source

Personally, I’d use wires.

for someone who’s asking this kind of question the best option is to use two power adaptors rather than them splicing and connecting without knowing what they are doing

wookiemeister said:

sibeen said:

wookiemeister said:

the next thing you should be thinking about how you are going to supply two devices from one power source

Personally, I’d use wires.

for someone who’s asking this kind of question the best option is to use two power adaptors rather than them splicing and connecting without knowing what they are doing

Mostly need to know what to look for at the shop

Riff-in-Thyme said:

wookiemeister said:

sibeen said:

Personally, I’d use wires.

for someone who’s asking this kind of question the best option is to use two power adaptors rather than them splicing and connecting without knowing what they are doing

Mostly need to know what to look for at the shop

i’d just buy two adaptors if I were you

what does the connection look like as in what does the jack look like? what kind of plug head would you need?

oh yes if you are using a plug going into a jack have a look at how the device tells you what kind of polarity is needed

some plug heads will have positive in the centre or if you position the head the other way it makes the positive on the outside connection – normally the thing you are powering will have some clue somewhere on it (a small diagram telling you positive centre or outside)

KJW said:

Riff-in-Thyme said:

KJW said:

It’s not really an option because it also assumes that the load is passive, which is unlikely.

analogue to digital audio converter(1 each way)

Then no. That load would be active (ie transistors).

Actually, there’s a more significant reason why the series option is not an option. Even if one could balance the loads, the grounds would be at different potentials.

>>Actually, there’s a more significant reason why the series option is not an option. Even if one could balance the loads, the grounds would be at different potentials”

Reminds me of all those UHF radio warranty returns when they first came out, farmers would pick the wrong battery of their two twelve volt batteries in series and the antenna base or radio chassis would ground, and, well, 12+12=24.

changing subject

have you have a leg twitch that happens once in a blue moon?

I just had one, I started feeling it somewhere along my spine , travelling down my leg to the foot then bang, the whole leg twitches

>>I just had one, I started feeling it somewhere along my spine , travelling down my leg to the foot then bang, the whole leg twitches.

Bit of a thread derailment, but broadly electrical I suppose.
Not today, no, don’t believe i’ve even had an involuntary erection for a couple of days.
I’m sure you were wondering about exactly that but were too shy to ask.

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KJW said:

KJW said:

Riff-in-Thyme said:

analogue to digital audio converter(1 each way)

Then no. That load would be active (ie transistors).

Actually, there’s a more significant reason why the series option is not an option. Even if one could balance the loads, the grounds would be at different potentials.

Nyet, no earth reference.

transition said:

>>I just had one, I started feeling it somewhere along my spine , travelling down my leg to the foot then bang, the whole leg twitches.

Bit of a thread derailment, but broadly electrical I suppose.
Not today, no, don’t believe i’ve even had an involuntary erection for a couple of days.
I’m sure you were wondering about exactly that but were too shy to ask.

you know me too well

how long has it been happening fsm?

the first step is to stop the denial

sibeen said:

KJW said:

Actually, there’s a more significant reason why the series option is not an option. Even if one could balance the loads, the grounds would be at different potentials.

Nyet, no earth reference.

I think you would find that the potential difference between the grounds of the two devices powered in series from the one 10V power adapter would be 5V or thereabouts.

KJW said:

sibeen said:

Nyet, no earth reference.

I think you would find that the potential difference between the grounds of the two devices powered in series from the one 10V power adapter would be 5V or thereabouts.

The potential of the two devices may be floating but one device will still be 5V or thereabouts above the other device.

KJW said:

KJW said:

sibeen said:

Nyet, no earth reference.

I think you would find that the potential difference between the grounds of the two devices powered in series from the one 10V power adapter would be 5V or thereabouts.

The potential of the two devices may be floating but one device will still be 5V or thereabouts above the other device.

Of course, but does that matter?

morrie said:

KJW said:

KJW said:

I think you would find that the potential difference between the grounds of the two devices powered in series from the one 10V power adapter would be 5V or thereabouts.

The potential of the two devices may be floating but one device will still be 5V or thereabouts above the other device.

Of course, but does that matter?

If you want to connect them either to each other or to something else common to both, then yes it does matter.

KJW said:

morrie said:

KJW said:

The potential of the two devices may be floating but one device will still be 5V or thereabouts above the other device.

Of course, but does that matter?

If you want to connect them either to each other or to something else common to both, then yes it does matter.

Yes, if you wish to bus the devices together it will be an issue, if not then it won’t be an issue.

Of course, I still wouldn’t do it :)

KJW said:

morrie said:

KJW said:

The potential of the two devices may be floating but one device will still be 5V or thereabouts above the other device.

Of course, but does that matter?

If you want to connect them either to each other or to something else common to both, then yes it does matter.

If they are in series, then they are connected to each other by definition, aren’t they?
I see what you mean about connecting them both to something else though. That might be a problem.

>>Of course, but does that matter?

Generally you keep rails uniform to avoid complications and accidents. Common grounds make it all a bit easier to think about too.

Beyond the problem of unbalanced loads creating inproper voltages in the case the supply weren’t regulated, you could ground the centre which’d have it be like a +/- split supply, if you wanted.

I love these topics where advice abounds despite almost universal ignorance of the subject.

gaghalfrunt said:

I love these topics where advice abounds despite almost universal ignorance of the subject.

That’s why I’m only watching.

gaghalfrunt said:

I love these topics where advice abounds despite almost universal ignorance of the subject.

it starts after the question has been answered

there wouldn’t be a voltage difference between “grounds” or earth or a return circuit

1 there would most likely be no earth involved

2 the return circuits are connected so no voltage difference would be found in a parallel circuit

>>I love these topics where advice abounds despite almost universal ignorance of the subject.

My mum was a diode.

wookiemeister said:

there wouldn’t be a voltage difference between “grounds” or earth or a return circuit

1 there would most likely be no earth involved

2 the return circuits are connected so no voltage difference would be found in a parallel circuit

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

KJW said:

wookiemeister said:

there wouldn’t be a voltage difference between “grounds” or earth or a return circuit

1 there would most likely be no earth involved

2 the return circuits are connected so no voltage difference would be found in a parallel circuit

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

KJW, that makes no sense to me. The output of a power adaptor is floating, as you have mentioned. How is a ‘ground loop’ going to be established?

If it was an isolated 5V battery would you have the same concerns?

KJW said:

wookiemeister said:

there wouldn’t be a voltage difference between “grounds” or earth or a return circuit

1 there would most likely be no earth involved

2 the return circuits are connected so no voltage difference would be found in a parallel circuit

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

it all depends on the load

i’m assuming that this device could just use two separate powersupplies

in this case with the load the first place to start about how the load should be powered is with the manual

how does the manual say the load should be powered?

sibeen said:

KJW said:

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

KJW, that makes no sense to me. The output of a power adaptor is floating, as you have mentioned. How is a ‘ground loop’ going to be established?

If it was an isolated 5V battery would you have the same concerns?

Maybe I’m using the term “ground loop” inappropriately, but the point is that each device will create its own ground reference relative to the power supply rails, and the two devices may do this differently so that the ground reference of one device relative to the negative rail will differ from the ground reference relative to the negative rail in the other device. For two separate power supplies, this is not a problem. But for one common power supply, the two grounds will then be at different voltages and when connected together, a current will flow.

KJW said:

sibeen said:

KJW said:

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

KJW, that makes no sense to me. The output of a power adaptor is floating, as you have mentioned. How is a ‘ground loop’ going to be established?

If it was an isolated 5V battery would you have the same concerns?

Maybe I’m using the term “ground loop” inappropriately, but the point is that each device will create its own ground reference relative to the power supply rails, and the two devices may do this differently so that the ground reference of one device relative to the negative rail will differ from the ground reference relative to the negative rail in the other device. For two separate power supplies, this is not a problem. But for one common power supply, the two grounds will then be at different voltages and when connected together, a current will flow.

the manual for the load should show it should be powered

KJW said:

sibeen said:

KJW said:

I have considered the idea of powering two devices from the one power adapter (connected in parallel), and consider it to be a bad idea. With two power adapters separately powering the two devices, the two devices have independently floating voltages, and the ground wire that connects the two devices is what determines the internal voltages of one device relative to the internal voltages of the other device. But when the one power adapter powers both devices, then the internal voltages of one device relative to the internal voltages of the other device are already determined without connecting the devices together via the ground wire. Thus, when the devices are connected together via the ground wire, there is strong risk of creating a ground loop.

KJW, that makes no sense to me. The output of a power adaptor is floating, as you have mentioned. How is a ‘ground loop’ going to be established?

If it was an isolated 5V battery would you have the same concerns?

Maybe I’m using the term “ground loop” inappropriately, but the point is that each device will create its own ground reference relative to the power supply rails, and the two devices may do this differently so that the ground reference of one device relative to the negative rail will differ from the ground reference relative to the negative rail in the other device. For two separate power supplies, this is not a problem. But for one common power supply, the two grounds will then be at different voltages and when connected together, a current will flow.

I must admit that you’re losing me here.

If a device is powered from a 5 volt supply, normally the negative of the supply will be considered to be the ground – whether there is an actual connection to a ground reference or not. Now if both devices are connected to the same supply then the positive rail and the negative rails are going to be at the same potential. How do the grounds differ in this case?

> but the point is that each device will create its own ground reference relative to the power supply rails

The negative rail will be the groung reference.

KJW said:

Maybe I’m using the term “ground loop” inappropriately, but the point is that each device will create its own ground reference relative to the power supply rails, and the two devices may do this differently so that the ground reference of one device relative to the negative rail will differ from the ground reference relative to the negative rail in the other device. For two separate power supplies, this is not a problem. But for one common power supply, the two grounds will then be at different voltages and when connected together, a current will flow.

If you could be sure that both devices are using the negative rail as the ground reference, then this it will be fine. But it requires that one knows the internal circuitry of the two devices to be sure. However, for audio devices, the ground is usually midway between the rails. Even if both audio devices have their grounds set midway between the rails, the two ground voltages might not be precisely equal because this depends on the tolerances of the components that split the power supply. Thus, one may still have a small current between the grounds of the two devices, and for high-fidelity audio, this is a bad thing.

To indulge

If you used a single 10 Volt plug pack say, and were crazy enough to split it rather than just dropping the voltage down, you could use the two series loads as a rough voltage divider, but really you have to regulate that centre voltage relative to +/- rails . This way if the outputs are some AC or digital signal and meet each other somewhere you might drop a capacitor in the line and isolate/couple them, and you have the common ground so outputs don’t influence each other in undesirable ways or the entire arrangements. Of course a capacitor isn’t required, you could throw in a transistor or fet or whatever and have both looking like operating between the same supply rails. If the phase relationship between the two were important it’d be a bit more demanding maybe.

Shuteye time.

It’s an A/D converter. I’d be very surprised if a split rail system was used, actually, I’d be stunned:)

sibeen said:

I must admit that you’re losing me here.

If a device is powered from a 5 volt supply, normally the negative of the supply will be considered to be the ground – whether there is an actual connection to a ground reference or not. Now if both devices are connected to the same supply then the positive rail and the negative rails are going to be at the same potential. How do the grounds differ in this case?

> but the point is that each device will create its own ground reference relative to the power supply rails

The negative rail will be the groung reference.

It should be kept in mind that I’m talking about a situation where one device outputs a signal voltage to the other device’s input. The ground wire that connects the two devices is the ground reference I’m referring to and this need not be the same as the power supply rails.

>>It’s an A/D converter. I’d be very surprised if a split rail system was used, actually, I’d be stunned:)”

The point though is the crazy indulgence of getting two 5 Volt supplies for two 5 Volt devices from a single 10 Volt supply without simply dropping the voltage down to 5 Volts, along with the possibility they may meet somewhere.

sibeen said:

It’s an A/D converter. I’d be very surprised if a split rail system was used, actually, I’d be stunned:)

I was speaking in more general terms, but even for an A/D converter, there is still the analogue side to consider.

you probably have a few 5v adapters at home already.

nearly every phone, camera, etc uses 5v supply. USB chargers etc will be 5v

Martins said:

you probably have a few 5v adapters at home already.

nearly every phone, camera, etc uses 5v supply. USB chargers etc will be 5v

The reason I wanted to use a single power supply to power multiple devices was to get rid of all those adapters which take up so much space on a power-board.

KJW said:

Martins said:

you probably have a few 5v adapters at home already.

nearly every phone, camera, etc uses 5v supply. USB chargers etc will be 5v

The reason I wanted to use a single power supply to power multiple devices was to get rid of all those adapters which take up so much space on a power-board.

exactly. i have 9 going as it is

Riff-in-Thyme said:

KJW said:

Martins said:

you probably have a few 5v adapters at home already.

nearly every phone, camera, etc uses 5v supply. USB chargers etc will be 5v

The reason I wanted to use a single power supply to power multiple devices was to get rid of all those adapters which take up so much space on a power-board.

exactly. i have 9 going as it is

Roger,

Find one with a good capacity. The newer apple chargers are 10w (so two amp), and use it to power two devices that require 10w or less in total.

In fact connect as many as you like, as long as total power requirement is less than power capacity of the plug pack.

Connect devices in parallel.

The point being this is a better idea than a 10v charger with the devices in series.