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Author Topic: what does the apostrophe symbol mean in this exponential converter equation?  (Read 5139 times)

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Offline dentakuTopic starter

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what does the apostrophe symbol mean in this exponential converter equation?
« on: August 15, 2014, 01:16:19 am »
I just started reading a document on "log and exponential (antilog) circuits" from this document http://electronotes.netfirms.com/s019.pdf
It's make more sense to me now than I did the first time I stumbled onto it quite a while ago but I have a question about mathematical symbols.

In the first equation Ic = I'eqVBE/kBT

What does the apostrophe symbol " ' " mean?
I can plug in values as well as anyone else but when the equation contains symbols I don't understand it's not terribly useful.
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Offline c4757p

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #1 on: August 15, 2014, 01:18:22 am »
It tells you!

Quote
I' is the "reverse saturation current" ~ 10-12 amps
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Offline dentakuTopic starter

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #2 on: August 15, 2014, 02:13:21 am »
Quote from: c4757p on August 15, 2014, 01:18:22 am
It tells you!

Quote
I' is the "reverse saturation current" ~ 10-12 amps

Doh!

I read that but didn't notice it included the '.
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Offline T3sl4co1l

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #3 on: August 15, 2014, 02:32:27 am »
Usually denoted as "Is"..
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Offline KJDS

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #4 on: August 15, 2014, 09:35:55 am »
I was going to suggest that you hadn't cleaned your screen properly
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Offline T3sl4co1l

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #5 on: August 15, 2014, 12:24:30 pm »
Quote from: KJDS on August 15, 2014, 09:35:55 am
I was going to suggest that you hadn't cleaned your screen properly

I'd post some suggestions, but on second thought I probably shouldn't go searching for "how to clean your screen" links... ;D ;D
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Offline Mechatrommer

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #6 on: August 15, 2014, 12:35:39 pm »
using aposthrophe just to distiguish different variables of related or similar thing (just like OP to differentiate 2 type of current Ic and I') is not an elegant way. "Ic" symbol is ok but I' that stands for "Is" is not good, "Is" symbol is more elegant. as "'" usually means "inverse" or "image" of the variable. such as if Is is saturation current then Is' is its inverse or 1 / Is. next time pass the word to anybody who want to write something academic or to young kids in schools.
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Offline ctz

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #7 on: August 15, 2014, 02:19:55 pm »
This is a prime, not an apostrophe. It's really common in science, engineering and maths texts.

http://en.wikipedia.org/wiki/Prime_(symbol)#Use_in_mathematics.2C_statistics.2C_and_science

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Offline dentakuTopic starter

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Re: what does the apostrophe symbol mean in this exponential converter equation?
« Reply #8 on: August 16, 2014, 12:26:31 am »
Quote from: ctz on August 15, 2014, 02:19:55 pm
This is a prime, not an apostrophe. It's really common in science, engineering and maths texts.

http://en.wikipedia.org/wiki/Prime_(symbol)#Use_in_mathematics.2C_statistics.2C_and_science

Nice.
That was rather educational.
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