Engineers: Do you use the notation log for natural log or log base 10.

[Eeezee]

Originally posted by: hypn0tik

Originally posted by: Heisenberg

Originally posted by: hypn0tik

Originally posted by: Heisenberg
It wouldn't surprise me. Those wacky engineers use j for the square root of -1 too. Us physicists use the proper ln for natural log and i for sqrt(-1).

They do it because i is usually reserved for current.

We use log at University but ln in highschool. It annoys me a bit as in math courses it refers to base e, but in electronics courses, it refers to base 10.

We use I for current too, but we've mastered the subtle art of capitalization.

Ah, but capitalized values are used by us to refer to DC values while lower case for AC values. There is a difference between capitalized and lower case subscripts as well.

Circuits were invented by physicists. I is the same for DC and AC values (because it technically represents the exact some quantity).

However, if i is what you're using for the current in an AC circuit, then wouldn't j be the current density in an AC circuit? J is current density.

 

[TuxDave]

Originally posted by: DVK916

Originally posted by: hypn0tik

Originally posted by: DVK916

Originally posted by: JayHu
I use log to represent whatever base I'm working in.
I can usually figure it out. It's one of three choices: e, 10, 2. I can figure it out using the context. The markers can usually do so as well.

What usefullness does log base 10 have. Base e and 2 I understand, but how is 10 usefull.

Used extensively in EE for calculating gain and for making Bode plots.

Edit: Beat to it by KillerCharlie.

But is it used more than natural log.

I haven't ever seen any of my proffessors use log to be anything other than natural log. Strange how the same nation is used so differently in different fields of study.

It's used infinitely more than natural log in EE just because we work in terms of standardized units. A lot of things us dB as the unit of measurement so we have to use Log10

 

[DVK916]

Originally posted by: TuxDave

Originally posted by: DVK916

Originally posted by: hypn0tik

Originally posted by: DVK916

Originally posted by: JayHu
I use log to represent whatever base I'm working in.
I can usually figure it out. It's one of three choices: e, 10, 2. I can figure it out using the context. The markers can usually do so as well.

What usefullness does log base 10 have. Base e and 2 I understand, but how is 10 usefull.

Used extensively in EE for calculating gain and for making Bode plots.

Edit: Beat to it by KillerCharlie.

But is it used more than natural log.

I haven't ever seen any of my proffessors use log to be anything other than natural log. Strange how the same nation is used so differently in different fields of study.

It's used infinitely more than natural log in EE just because we work in terms of standardized units. A lot of things us dB as the unit of measurement so we have to use Log10

I talked to someone who is a ME and he said log base 10 is rarely used in ME, strange. Two engineering fields so different.

 

[hypn0tik]

Originally posted by: Eeezee

Originally posted by: hypn0tik

Originally posted by: Heisenberg

Originally posted by: hypn0tik

Originally posted by: Heisenberg
It wouldn't surprise me. Those wacky engineers use j for the square root of -1 too. Us physicists use the proper ln for natural log and i for sqrt(-1).

They do it because i is usually reserved for current.

We use log at University but ln in highschool. It annoys me a bit as in math courses it refers to base e, but in electronics courses, it refers to base 10.

We use I for current too, but we've mastered the subtle art of capitalization.

Ah, but capitalized values are used by us to refer to DC values while lower case for AC values. There is a difference between capitalized and lower case subscripts as well.

Circuits were invented by physicists. I is the same for DC and AC values (because it technically represents the exact some quantity).

However, if i is what you're using for the current in an AC circuit, then wouldn't j be the current density in an AC circuit? J is current density.

J isn't as commonly used as I in EE.

 

[SaturnX]

In EE, the lowercase i isn't a fixed value. When i is written, it implies i as function (generally of t).

So you've got:

I = DC Current
V = DC Voltage
i = i(t) = AC Current (which is a function)
v = v(t) = AC Voltage (which also is a function)

Thus for imaginary numbers the letter j is used, as you see i is reserved for current as mentioned above.

Current desnity is J.

--Mark

 

[SaturnX]

Originally posted by: hypn0tik

Originally posted by: Eeezee

Originally posted by: hypn0tik

Originally posted by: Heisenberg

Originally posted by: hypn0tik

Originally posted by: Heisenberg
It wouldn't surprise me. Those wacky engineers use j for the square root of -1 too. Us physicists use the proper ln for natural log and i for sqrt(-1).

They do it because i is usually reserved for current.

We use log at University but ln in highschool. It annoys me a bit as in math courses it refers to base e, but in electronics courses, it refers to base 10.

We use I for current too, but we've mastered the subtle art of capitalization.

Ah, but capitalized values are used by us to refer to DC values while lower case for AC values. There is a difference between capitalized and lower case subscripts as well.

Circuits were invented by physicists. I is the same for DC and AC values (because it technically represents the exact some quantity).

However, if i is what you're using for the current in an AC circuit, then wouldn't j be the current density in an AC circuit? J is current density.

J isn't as commonly used as I in EE.

Unless of course you're working with semi-conductor device physics But you knew that didn't you?

--Mark