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Electronic circuit part 1

Stranded vs solid wire



Stranded wire:-

  • Costly

  • Only for indoor application
  • Flexibility (not split when u twist it)
  • Better performance in high-frequency signal(because of reduce skin effect)
  • Skin effect reduce because of every individual strand have more surface area (overall increase surface area)
  • Power dissipation is better because of increased surface area or air gaps.
  • environment effect is more like corrosion.


Solid wire:-


  • Cheaper
  • It's mostly used in outdoor application
  • ruggedness
  • anti-corrosive
  • Skin effect more than as the Same gauge of a wire of strand.


Why V directly proportional to I in case of P, and why inversely proportional to I in case of R

Both are different qualities and different approaches, power is the measurement of work done by charge, and resistance is the measurement of the resist of the flow of electron.

e.g.Consider a circuit with voltage supply 220v and connect a purely resistive load like a bulb in parallel and you have to calculate power, and resistance of the bulb
Also, you know already the current of the circuit so u apply a formula for resistance measurement
R=V/I
After that, you have to calculate power so You will apply formula P=VI but both cases current and voltage are the same, And if u change the supply voltage so current also changes but both power/resistance have the same voltage/current.

Q: So questions is what does mean V∝1/I, V∝I.


A: if you have only two quality V and I And you decided that you will be compared both of them linearly and then non linearly.
For a load, When you compare it at the same time like this V∝I Then a new thing is made "Resistance" and then you also decided That you compare it like this V∝1/I then a new thing is made "Power".

It depends on you how you use the quantity of how you compare the quantity And when you compare it to different ways So you will get a different Constant of Proportionality.

More Explanation:
you also needs to know what is independent and dependent variable and constant quantities. And also controlled qualities.

Whichever value you can change, then it is your variable (unknown quantity) it may be the dependent and independent variable.
Whichever value you can't change which fixed then it is your constant(known quantity).

e.g. y=2x
Here y is a dependent variable that is dependent on x and x is the independent variable also here 2 is constant quality or known value.


Constant means known qualities also fixed


For equation P=VI
P∝V only if the current is constant,
P∝I only if voltage is constant,
V∝1/I only and only if power is constant.
Also
For equation V=IR
V∝I only & only if resistance is constant.
V∝R only if the current is constant,
I∝1/R only if the voltage is constant.

Both cases (V∝I and V∝1/I) are due to resistance/power being constant so let's compare P and R.
For equation P=VI
You can relate it to resistance R only if one of them is fixed quality (voltage same in parallel and current same in series), then replace it to ohm law V=IR,
P=I²R (P∝R only if the current is constant),

P=V²/R (P∝1/R only if the voltage is constant).

The relation between the voltage and the current (V∝I and V∝1/I) follow at the same time in a given load, And for both, different graphs are also made.
Because you have decided how you want to compare it.


Which is killer voltage or current
Credit: https://publicdomainvectors.org/


For human Depends upon resistance.
Why??
1) A) remember: when you connect a load in parallel, then Lower resistive load consumes high power in parallel. And
A higher resistive load consumes less power in parallel.
Vice-versa in series.
B)Also remember that a device withdrawal the current according to own load, for example:- a led bulb in home withdrawal a lower current compare a filament bulb In both causes voltage is same but current is different
2)In most cases that occur, a man accidentally touches a phase/hot, Because of which he connected in parallel suddenly and he completes the path of current through the earth.
Remember:- in parallel connection voltage is same for all devices, for human also same.
Human has 100kohm resistance of skin in dry conditions and 500ohm to 1kohm in wet conditions.
3) calculation:-
In dry conditions, humans have(let's supply voltage is 220v). then
V=IR
220volt=I*100000ohm
I=220/100000 A
I=0.0022A=2.2mA

In wet conditions human have:-
V=IR
220volt=I*1000ohm
I=220/1000 A
I=0.44A=440mA
Behind the scenes, there is also a big roll of distributed transformer (have more power than a battery)

4)a 30mA Ac at 60Hz and 500 mA DC is enough for damage and manipulate
ventricular fibrillation of heart.
A human can feel the current 1mA AC at 60Hz and 5mA DC.
Caution:-you should need to know what is 'resistive load' and 'inductive load'. I mentioned only resistive load here.
Motor,fan,pump,relay etc. etc. Are more inductive in nature. (needs a magnetic field, rating power like KVA, KVAR)

Human, bulb, computer, etc. Etc. They are more resistive in nature. (no need of magnetic field, rating power like KW).
Conclusion:- it's depends