Question about electricity

[basketcase]

yes it is

AC is the alteration of magnetic fields

DC is the chemical storage of excess electrons

altering the DC current does not change its basic DC nature

The only way to change the voltage in a DC circuit is to somehow create more electrons (to be simple) (or add a battery).

 

[basketcase]

Potency = Ejaculate flow X Thrust

I think you need some factor about how well the boys swim.

 

[basketcase]

Sometimes I wonder if Yoga is a high school student using terb to do his science homework.

 

[FAST]

Creation

The only way to change the voltage in a DC circuit is to somehow create more electrons (to be simple) (or add a battery).

There are numerous ways to increase the voltage in a DC circuit, a good example is the old camera flashes,...when you heard the wine increasing ,..so was the voltage.

Has nothing to do with "creating more electrons".

FAST

 

[shakenbake]

AND more importantly,...able to use smaller cables.

A side note, DC would be better for long transmission lines, less losses,...but more difficult to deal with in the end.

FAST

Would that have to do with the resistance due to 'skin effect' with AC? Maybe, that is one reason that they are looking at DC line transmission for the future, with locally distributed power systems.

 

[basketcase]

There are numerous ways to increase the voltage in a DC circuit, a good example is the old camera flashes,...when you heard the wine increasing ,..so was the voltage.

Has nothing to do with "creating more electrons".

FAST

Unless old flashes are different from the ones used now, that is by using a capacitor which stores current over a period of time until all of the energy is released in one burst. The total power is the same; small current for long time vs large current for a small time. Since P=E/t, E=Pxt, the energy is conserved.

 

[basketcase]

To increase DC voltage, use a DC/DC convertor

and DC is not the chemical storage of excess electrons

Yes, it's is a potential difference between the positive and negative terminals. I was trying to keep things simple for Yoga.

 

[shakenbake]

Transformers won't work with DC. It has to be AC because a the energy is transferred through a changing magnetic field which requires a changing electrical field. In a DC circuit, the electric field is constant.

Slight correction, I believe; you need a pulsating source at the primary. You don't need to change the direction of current flow. Electroplating lines have big thyratrons conencted at the primary to control the voltage at the secondary that comes out as partly filtered DC.

 

[basketcase]

Slight correction, I believe; you need a pulsating source at the primary. You don't need to change the direction of current flow. Electroplating lines have big thyratrons conencted at the primary to control the voltage at the secondary that comes out as partly filtered DC.

I agree, Again I was keeping it simple for Yoga's school project.

 

[massman]

You are right that people are making this more complicated than need be.

Power is measured in Watts and is useable energy no different than heat (btu's) or light (lumens) or even calories and can even be converted from one of these measurements to another.
Voltage is measured in Volts and is the electrical "pressure" and can also be referred to as electrical "potential"
Current is measured in Amps and is the electrical "flow"
Resistance is measured in Ohms and is the electrical "opposition" or "restriction" to flow

The reason induced voltage is not simply "free energy" is because the resistance values will not change regardless of if it is step up or step down. Because the resistance values will stay the same, the power values will also stay the same. Another way to say it is the voltage may be higher in a step up but the result will be current will decrease because resistance doesn't change. That is why some were showing the formulas.

Eg. If the resistance value of the whole system is 35k ohms and the voltage produced is 10k volts you will have a current of 3.5 amps. If you were to now insert a (let's say 1:2 ratio) step up transformer into the circuit, your induced voltage will become 20k volts. But a transformer doesn't change the resistance of the whole system (in theory) so you still have 35k ohms resistance which will now result in a current of 1.75 amps. So to figure out the actual useable energy (watts) you multiply volts by amps.
No transformer: 10000 x 3.5 = 35000 or 35k watts
With transformer: 20000 x 1.75 = 35000
So now you can see that even though the voltage is stepped up, the useable energy is constant as many of the previous posters also said.

Volts = amps x ohms; Watts = amps x volts

Clear?

Excellent. You should teach highschool and university physics.

 

[FAST]

Huuuum

Would that have to do with the resistance due to 'skin effect' with AC? Maybe, that is one reason that they are looking at DC line transmission for the future, with locally distributed power systems.

MY understanding is that there is induced losses with AC, but obviuosly not DC, but I may be wrong.

FAST

 

[FAST]

Don't touch

Unless old flashes are different from the ones used now, that is by using a capacitor which stores current over a period of time until all of the energy is released in one burst. The total power is the same; small current for long time vs large current for a small time. Since P=E/t, E=Pxt, the energy is conserved.

We were talking about voltage, not power, a much higher voltage than available from batterys was required to fire the flash, in the order of hundreds of volts, and yes you are correct about the "charge" being stored in a cap., but the voltage still had to be high.

FAST

 

[FAST]

Brings back memorys

Slight correction, I believe; you need a pulsating source at the primary. You don't need to change the direction of current flow. Electroplating lines have big thyratrons conencted at the primary to control the voltage at the secondary that comes out as partly filtered DC.

I thought thyratrons were long gone in plating and welding and replaced with SCRs and triacs ??

Do you remember saturable core reactors ??

FAST

 

[basketcase]

Maybe we're talking apples and pears. The source voltage applied to the circuit is a constant. The effective voltage over the capacitor can change. As the charge builds up on the plates, there is a voltage drop in response to the existing charge and the is discharged at an effectively higher voltage.

What is significant though is the capacitor stores electric potential energy and that energy comes from the source (constant V). The benefit of a capacitor and the reason for the flash is the rapid discharge of the capacitor meaning the energy that is stored over an extended period is released quickly meaning a low power is turned into a high power for a brief time. That does result in an effective voltage increase for a short time and the rest of the time zero voltage. The net effect is that the total energy to the load would be the same with or without the capacitor; all that is effectively changing is the rate it's used at.

We can get a lot more involved if you want to discuss capacitor circuits more complex than nice and simple series RC circuits but since that first bit of equations went over yoga's head, we'd probably be just trying to impress each other with how much we know.

 

[shakenbake]

I thought thyratrons were long gone in plating and welding and replaced with SCRs and triacs ??

Do you remember saturable core reactors ??

FAST

Ah, FAST, SCR and Triacs are Solid State Thyratrons. That was my understanding of the term nowadays. Rather, now that I think about it, I should have used the word, Thyristor!

 

[FAST]

Big magnet

Ah, FAST, SCR and Triacs are Solid State Thyratrons. That was my understanding of the term nowadays. Rather, now that I think about it, I should have used the word, Thyristor!

AGREE, I think Thyristor is what I was refering to as Triacs, different names for the same device.

Or if I was to be a real smart ass,...anti parallel SCRs.

I used to work for a company that made DC power supplies for plating,... I used a piece of angle iron as the load, would get real warm, and suck a screw driver out my pocket if I got too close, and destroy mechanical watches.

FAST

 

[Yoga Face]

This is taught in Grade 11 physics.
Don't worry Yoga face. You'll learn all the reasoning behind it this semester.

And "who'syourdaddy" I'll admit to have dropped the decimal places however the analogy still remains true to explain to the OP why there is no free energy in this type of arrangement. It's been a while since I've thought to myself "At 600 an amp is a horse" - I pay other people to do that now and don't have to wash my hands as often.
It the generator being driven by the turbine puts out 10.0 horsepower then in a perfect world ignoring the particular characteristics of this particular turbine it's output would be 7500 watts.
As long as you work from the basic concept of the WATT = Volts x Amps he will see that as you double the Voltage the current has to half to remain the same.

I have a grade 10 education and I am not in school so as these questions pop into my head I have a need to find the answer to prove to mself I am not dense when it comes to conceptual matters

 

[Yoga Face]

You are right that people are making this more complicated than need be.

Power is measured in Watts and is useable energy no different than heat (btu's) or light (lumens) or even calories and can even be converted from one of these measurements to another.
Voltage is measured in Volts and is the electrical "pressure" and can also be referred to as electrical "potential"
Current is measured in Amps and is the electrical "flow"
Resistance is measured in Ohms and is the electrical "opposition" or "restriction" to flow

The reason induced voltage is not simply "free energy" is because the resistance values will not change regardless of if it is step up or step down. Because the resistance values will stay the same, the power values will also stay the same. Another way to say it is the voltage may be higher in a step up but the result will be current will decrease because resistance doesn't change. That is why some were showing the formulas.

Eg. If the resistance value of the whole system is 35k ohms and the voltage produced is 10k volts you will have a current of 3.5 amps. If you were to now insert a (let's say 1:2 ratio) step up transformer into the circuit, your induced voltage will become 20k volts. But a transformer doesn't change the resistance of the whole system (in theory) so you still have 35k ohms resistance which will now result in a current of 1.75 amps. So to figure out the actual useable energy (watts) you multiply volts by amps.
No transformer: 10000 x 3.5 = 35000 or 35k watts
With transformer: 20000 x 1.75 = 35000
So now you can see that even though the voltage is stepped up, the useable energy is constant as many of the previous posters also said.

Volts = amps x ohms; Watts = amps x volts

Clear?

But how can the amps change ? an ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6.241 × 1018 electrons, or one coulomb per second constituting one ampere.

You are saying the amount of electrons flowing in the conductor becomes less with increased Voltage even though the resistance has not changed

 

[Yoga Face]

Yes, it's is a potential difference between the positive and negative terminals. I was trying to keep things simple for Yoga.

Is not the potential difference in a DC battery the number of electrons in each end of the battery being a different number (but the atoms being the same number so the electrons want to travel from the electron rich to the electron poor atoms) ?

The loss of an electron is called oxidation. Its opposite is reduction.

The loss of an electron increases the charge by +1.

 

[IM469]

My turn to display my warped understanding of electromagnetism:

Putting ANY form of DC into a xfmr would saturate the core of the xfmr.

First - we seem to to be mixing power transmission (DC vs AC) with electronics. DC = direct current and indicates that there are fixed polarities in which the current flows only one direction. Alternating current is named because the current flows one direction and then stops and flows the opposite direction. In the early days Edison was a supporter of DC transmission and Tesla was a supporter of AC. As described in a few posts, the ability for transformer to transfer power to higher voltages (same power with lower currents) allowed AC power to be transported farther and much more efficiently than DC. For this reason Tesla and AC is now used worldwide to move power from the location it is generated to the markets that are using it.

In electronics, AC is mixed with DC in virtually every type of manufactured entertainment device. This is because in the old vacuum tubes as well as modern semiconductors - the current in these devices only operate in one direction (DC). In this case the current in one direction is changing according to the AC signal - that is current in one direction is varying by the amount of the A/C signal. One method used in the electronic circuits to separate the AC signal from the DC is to put both through a transformer. Since only the AC passes through transformer, the signal be removed from the DC.

Too much DC (current) can saturate the transformer (the magnetic field reaches a limit that will not vary with the AC signal component) but it is the exception that is avoided.

To increase DC voltage, use a DC/DC convertor

While the outside of the package has DC in and DC out, what is really happening is DC -> AC -> Transformer -> New AC voltage -> New DC voltage.

Maybe we're talking apples and pears. The source voltage applied to the circuit is a constant. The effective voltage over the capacitor can change. As the charge builds up on the plates, there is a voltage drop in response to the existing charge and the is discharged at an effectively higher voltage.

What is significant though is the capacitor stores electric potential energy and that energy comes from the source (constant V). The benefit of a capacitor and the reason for the flash is the rapid discharge of the capacitor meaning the energy that is stored over an extended period is released quickly meaning a low power is turned into a high power for a brief time.

Capacitors are much like a battery in that they can store a charge. When connected to a DC voltage, current will rush in until the voltage equals the source DC voltage. If the DC varies, the capacitor will discharge or absorb current to match the DC voltage. This property can be used in two ways:
1) If you put one side of the capacitor on a DC that has ad AC signal included and measure the current (typically through a resistor as voltage) the AC signal has been separated from the DC. Capacitors are used routinely in electronics to separate AC (signals) from DC.
2) The ability of capacitors to store energy allow it to slowly accumulate energy from a limited power source and the released it quickly but the voltage and accumulated power do not change. When the capacitor dumps its load suddenly, it is basically short circuited through a transformer. The accumulated energy is transferred to the coil that is wound to provide a high voltage out (in a car - this is the ignition coil) which fires the spark plugs, flash tube, laser or lifts the cow a few inches from the ground (depending on what you are doing with the pulsed high voltage)