I’m trying to make a circuit that takes a input of 120AC and can have anything plugged in and will send only what the device needs and have the rest gotten rid of without having to manually configure things. Ideally i need a rough concept of how i would go about figuring out how to do that.

 

You can't. What if I plug in a 10 Ω resistor to your device. How much (of whatever, since you don't specify what it is your device is sending) should your device send to it?

If you can't answer that for a simple resistor, how can you hope to answer it for "anything" that might get plugged into it?

 

could it not send a pulse through then subtract what it gets back from what it sent and then send what the new total is in?

 

could it not send a pulse through then subtract what it gets back from what it sent and then send what the new total is in?

What does this even mean?

Again, I plug a 10 Ω resistor into your device. What SHOULD it send to it? Forget about how it goes about doing it, what should the end result be? Should the resistor have 1 V across it? 10 V across it? 1000 V across it? What?

If YOU can't even figure out what should be sent to a 10 Ω resistor, how can you possibly expect some device to be able to do it?

And, again, you won't specify just what it is that is being sent. Voltage? Current? Power? What?

But let's look at your suggested approach.

Your device sends a pulse (of what?) through the resistor.

Just what is it that the resistor is supposedly "sending back" to your device?

 

consider it like this if i send 12v 4a through whatever is plugged in and it uses 3amps the 1 amp that it didn’t use will be left over and the device gets that leftover amp coming out of the negative and no longer send that extra amp.

In regards to how much you send in you can gradually increase amps sent in until some of the amps is not being used and that is measured.

 

Well, let's piece of thick wire is plugged in.
It can use up to some thousands amp.
What will to do your appliance?
Will it send 1, 2, 10, 100, 1000 A?
ADDED:
Simple wall outlet always send to device
exactly such current, which device need to be consume.

 

well it depends on how the device is eventually designer but most likely the amount it ends up settling on sending through would be extremely small or it might just completely break depending on how many decimals it rounds to. That is a good point though

 

consider it like this if i send 12v 4a through whatever is plugged in and it uses 3amps the 1 amp that it didn’t use will be left over and the device gets that leftover amp coming out of the negative and no longer send that extra amp.

In regards to how much you send in you can gradually increase amps sent in until some of the amps is not being used and that is measured.

You can't send 12 V and 4 A though anything, unless that something has an impedance of 3 Ω.

There is no "left over" -- you don't get to "send in" a bunch of amps and see how much is somehow "left over".

But let's say that your device, internally, has the ability to do what you are suggesting.

Again, I connect a 10 Ω resistor to your device.

Now your device tries to send 12 V and 4 A through this resistor. At 12 V, the resistor draws 1.2 A, so there is 2.8 A "left over".

Now what?

You say that you no longer send that extra current. What does that mean? That now you send 12 V and 1.2 A so that there is no "left over" current? How is that any different than just outputting 12 V to begin with and being done with it? And how has this somehow determine what the resistor needs?

I have asked you a couple of times -- what should the output of your device be if I plug in a 10 Ω resistor?

If you can't tell me that, then you have no idea what your device should even try to accomplish, and if you don't know that, how can you possibly even attempt to figure out how it can go about accomplishing it?

 

alright so if in put just 12v there is always going to be leftover current (unless there is not enough) that leftover current is wasted resources spent on generating that power and did not need to be there so if i can just not send that i can minimize the amount of resources spent on energy generation or store said excess energy for latter use

The resistor question is not a good representation of how it would be used because with the resistor there is not going to be fluctuations in the circuit and if i need to send x power to overcome the resistor thats easy to figure i want to know how much exactly do to run a say a calculator and i want to be able to just plug it in and not spend hour figuring out what the exact number is

 

Let's say you plug a 60 watt (incandescent) bulb into an outlet that can supply over a thousand watts? The bulb draws 60 watts. Nothing is wasted. No excess power is generated.

Ok, well what if you only plug in a 4 watt nightlight bulb? Still no wasted power; it draws 4 watts, despite how much the outlet can deliver.

If you supply the correct voltage, the device will draw its design wattage. There is no way to for a mysterious invention to know what voltage a device is designed for other than it doesn't work or smoke and flames come out.

 

okay but said bulbs plug into a special plug just for bulbs i want something that i can plug literally anything into and it will only ever give it exactly what it needs

 

okay but said bulbs plug into a special plug just for bulbs i want something that i can plug literally anything into and it will only ever give it exactly what it needs

The world most often doesn't care what you want.

With a lot of studying, maybe you can figure out the impossible. You appear to be short on some fundamental principles.

 

Do you have any resources that you would recommend then?

 

Do you have any resources that you would recommend then?

https://www.allaboutcircuits.com/textbook/direct-current/chpt-1/voltage-current/

 

alright so if in put just 12v there is always going to be leftover current (unless there is not enough) that leftover current is wasted resources spent on generating that power and did not need to be there so if i can just not send that i can minimize the amount of resources spent on energy generation or store said excess energy for latter use

When you plug a lamp into a wall outlet, do you spend a lot of time figuring out anything?

When you plug a phone charger into a wall outlet, do you spend a lot of time figuring out anything?

When you plug a space heater into a wall outlet, do you spend a lot of time figuring out anything?

No, you don't. The only thing you need to make sure is that whatever you plug into a 120 VAC outlet is rated for 120 VAC, which is normally taken care of by putting the kind of plug that only fits into a suitable 120 VAC outlet onto whatever it is. As long as that is observed, whatever you plug in will draw exactly how much current it needs. There is no current left over that is either being wasted or can be saved for later use. You need to learn what voltage and current are and what Ohm's Law is and how it relates voltage and current (in certain kinds of devices, namely ones that are ohmic).

The device you are trying to create serves zero purpose as long as long as what you are plugging into it is rated for 120 VAC. So the only possible purpose your new device (let's call it a "smart outlet") can serve is if it can somehow sense what voltage some arbitrary thing that gets plugged into it is designed to operate from, and that cannot be done. Sure, you could design devices that are capable of communicating with your smart outlet so that your device can automatically configure itself to output the right voltage, but that will only work with devices that have been specifically designed to be compatible and communicate with your smart outlet.

The resistor question is not a good representation of how it would be used because with the resistor there is not going to be fluctuations in the circuit and if i need to send x power to overcome the resistor thats easy to figure i want to know how much exactly do to run a say a calculator and i want to be able to just plug it in and not spend hour figuring out what the exact number is

If it's so easy to figure, why can't you figure it out?

You can't figure it out because the answer can't be figured out!

That 10 Ω might be a 1/4 W resistor, in which case the maximum voltage that can be placed across it is about 1.5 V, or it might be a 1200 W space heater, in which case it needs 120 V put across it, or it might be a 5 kW furnace element that needs to be powered by 220 V. In all three cases, the resistance is 10 Ω. Unless you can somehow magically determine what voltage it is designed to operate from, you are not going to be able to design your smart outlet to let someone plug in each of those three things and expect anything but bad things to happen.

 

@WBahn
I really admire your patience and your ability to put difficult ideas across to a new learner.

Wish I had that skill

 

THERE IS NO SUCH THING AS "LEFT OVER CURRENT." What does exist is unused supply capability!
What I must have missed is a statement of what different voltages that items plugged into an outlet will require.

If the application requires only the voltage supplied at the outlet, it will only consume the current it requires. That can be verified by means of OHMS LAW: Current = VOLTAGE divided by RESISTANCE ( I=E/R)
Under normal conditions it can not work any other way.. Of course, for alternating current (AC) circuits it becomes : Current = voltage divided by Impedance. That requires vector math, which is a bit more complex.

 

alright so if in put just 12v there is always going to be leftover current (unless there is not enough) that leftover current is wasted resources spent on generating that power and did not need to be there so if i can just not send that i can minimize the amount of resources spent on energy generation or store said excess energy for latter use

The power source for me is hydro generated from a dam 600mls away.
Every day they generate several megawatts of power, I use very little of that, I know! its a waste, but I have no where to store it !!

 

ONCE AGAIN, there is no such thing as "LEFT OVER CURRENT"!!!!!
Certainly there does exist unused capability, but unless you are paying for available power capacity rather than Power consumed, that is not a waste.

If you are running a Ten Kilowatt generator to power a one watt night-light, as an example, that is a great waste of generator capacity, but there is not a bit of left over current.

Next, consider a car with an engine claimed to produce 200 Horsepower. You might be able to use that much power for a very quick startup, but to continue using it for more than a very quick merge into fast traffic will result in exceeding any speed limit.
My point being that almost all good designs include a bit of capability beyond the present requirement. The one time my employer had a contract engineer design a system, it was designed with no excess capacity at all. Unfortunately it was also designed for a 20 degree C environment. The result was that when it was used in a 24 degree C environment it over heated a bit, causing problems. The result was that after the system was built and tested, I had to design in a larger heat sink.

 

ONCE AGAIN, there is no such thing as "LEFT OVER CURRENT"!!!!!
Certainly there does exist unused capability, but unless you are paying for available power capacity rather than Power consumed, that is not a waste.

If you are running a Ten Kilowatt generator to power a one watt night-light, as an example, that is a great waste of generator capacity, but there is not a bit of left over current.

Next, consider a car with an engine claimed to produce 200 Horsepower. You might be able to use that much power for a very quick startup, but to continue using it for more than a very quick merge into fast traffic will result in exceeding any speed limit.
My point being that almost all good designs include a bit of capability beyond the present requirement. The one time my employer had a contract engineer design a system, it was designed with no excess capacity at all. Unfortunately it was also designed for a 20 degree C environment. The result was that when it was used in a 24 degree C environment it over heated a bit, causing problems. The result was that after the system was built and tested, I had to design in a larger heat sink.

It's a common misconception that comes from thinking that current is electrical energy.