The first Post of ＜VQ = Energy, VI = P＞ended (not concluded) as
"
We can make a simple modification of the equation VQ = Energy, we can get
V = Energy / Q , or
Voltage is Energy per Charge.
"
Meanwhile as I repeatedly used the following equation.
dQ
I (current) = -------
dt
In both equations Q appears. So we can play with these two equations and Q.
＜VI = P＞ is fine but can we simply multiply V by I ? Or V times I is possible ? We can do on paper but is this actually or physically or electrically possible ?
It dos not seem allow us to do ＜V x I ＞ as the units differ. ＜V1 +/－V2＞、＜I1 +/－I2＞are OK (while V1 x V2, I1 x I2 will be OK?)
On paper or in our head
Energy dQ
V x I = --------- x --------
Q dt
Energy x dQ
= -----------------
Q x dt
Energy
= ------------- (= Power = the time ratio of Energy)
t
as I (current) is the time ratio of Q flow (movement)
＜V x I ＞ will be the time ratio of Energy ＜flow (delivery)＞ or use, storage.
In terms of words
＜work ＞is usually used as ＜work (is) done＞ and seldom used as ＜work will be done＞or ＜potential work＞while ＜energy＞is usually used as ＜energy is (has been) used＞ as well as ＜power＞as ＜power is (has been) used＞. But ＜energy＞and ＜power＞ also used as ＜to be used＞and ＜potential energy / power＞are quite natural usage.
Potential energy / or potential power makes work done.
Work needs energy / or power to be done. (Work to be done needs energy / or power.)
Work is more like <result> while Energy and Power are more like <cause>.
---------
Through x Across
＜Through x Across＞can be imagined as multiplication or product and has some meaning even the units differ.
^ V
Ｉ
Ｉ
Ｉ
＜－－－－－－－－＞ I or Q
Ｉ
Ｉ
Ｉ
ｖ
For instance the vertical line indicates V (Voltage) and the horizontal line indicates I (current). ＜V x I＞indicates the area (like Vcm x Icm = VIcm2). The (area) size of VIcm2 changes when V or I changes or both change. The problems are
1) the units of V and I differ. V in Volt, I in Ampere. So VI = VI Volt-Ampere.
2) I is the time ratio of Q quantity, either constant DC or periodically changes (AC) including the change of direction. This seems to make things complicated. The point is that either direction of current flow work is done - Power or Energy is used.
We can say the same thing to QV = Energy
1) the units of V and differ. V in Volt, Q in Coulomb. So VQ = VQ Volt-Coulomb.
Another point is that Q moves when work is done. When Q stays and does not move work cannot be done. Voltage is basically potential but make Electric Field ( a kind of Field Theory). The unit of Electric Field Strength (measurement of Electric Field) is V/m. <m> is meter so this show the distance between the two points which leads to the difference. When Q moves or I flows in the Electric Field made by V work is done.. But what makes Q move or I flow. The above sketch can be changed to
^ V＋
＜－－－－－－－－＞ I or Q
ｖ
V－
The space represents the electric field. (we do not elaborate here but the current flow or more correctly the change of current flow (di/dt) produces voltage - Electro-Motive Force)
Another drawing
－－－－
^ －－－－－ Ｉ Load Ｉ －－－＞
Ｉ －－ －－ Ｉ
－ (+) Ｉ
V Ｉ
－ (-) Ｉ
Ｉ Ｉ
＜－－－－－－－－－－－－－ V
Arrows show the direction of Current or movement of Q. Load is usually use Energy or Power like a Resistor (Heater), Light Bulb or LED Lamp. Generating Heat or Emitting Light can be said as "Work is done" and therefore " Energy and/or Power are used". If "Work is not done" then " Energy and/or Power have not been used yet".
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