datasheettransistors
I am going through this tutorial, they state that "Ic is the current through the collector and function of the transistor" however I haven't really been able to look at the data sheet and figure out where that information is. I am guessing you need to calculate it somehow but I am not sure what information to use.
I see the section where they give some typical values of beta with different ranges of current but I don't get how that is a function of the transistor.
Thanks
Image taken from maplesoft.com
If you look at the Ebers-Moll model, you can see that each junction is desctibed by a diode and a voltage controlled source. So the collector current will be, as in the first equation, dependent on Vbc (not Vbe) with the Shockley equation, but also on Ib, like in the second equation.
The second factor will be of some meaning only if Vb > Vc, which happens in the saturation region, where the B-C junction is forward biased and current can flow from the base to the collector. In the forward-active (also called linear) region, the B-C junction is reverse biased and the collector current is basically only given by Beta.
How to find the pulse current rating? LOOK IN THE DATASHEET, of course.
I don't understand what is so ambiguous about "maximum". If the datasheet says the maximum current is 200 mA, then that is all you can put thru the device and expect it to adhere to the other specs. Some datasheets may provide a additional maximum pulse current spec. If so then there is your answer. If not, the "maximum" current spec is still your answer. There is nothing ambiguous here.
If you are asking what you can get away with despite what the datasheet says, then you've come to the wrong place. We do engineering here, which wishful thinking and religious beliefs have nothing to do with.
Best Answer
They just mean that different transistors have different values of beta.
Since it's a beginners tutorial they're glossing over the fact that even for a given transistor, beta will vary depending on temperature, bias point, etc.
Some data sheets will use the symbol hfe instead of \$\beta\$.
Usually the temperature dependence will be given only as a typical curve, not a minimum/maximum specification. Even the nominal beta spec range will usually be quite broad, pften with ratios in the neighborhood of 5:1 between maximum and minimum.
What this means is you need to design your circuit (usually by including feedback) so that the overall behavior of the circuit is insensitive to the beta of the individual transistors.