Help with transistor datasheet

[Genji Shimada]

On this datasheet of PN2222A bipolar transistor

it is said that Vcesat at Ic/Ib=10 is about 0,3volts. However in the Icollector vs Vcesat graph for the same transistor that I will be posting immediately after I post this thread cause I can't add one more image here, it is shown that Vce hardly even exceeds 0,2 volts at 500mAmps. And I am confused, what should I look at to find what value of Vcesat to expect at given collector current?

 

[Genji Shimada]

And here's the graph

 

[Jony130]

figure 11 show a typical values not the maximum one.
http://www.aoc.nrao.edu/~pharden/hobby/HG_DS1.pdf
https://www.physicsforums.com/threa...-gain-in-saturation-mode.865392/#post-5432159

 

[Genji Shimada]

figure 11 show a typical values not the maximum one.
http://www.aoc.nrao.edu/~pharden/hobby/HG_DS1.pdf
https://www.physicsforums.com/threa...-gain-in-saturation-mode.865392/#post-5432159

Hmm, so if we look at this datasheet, the developers have tested the transistor under 150mA Ic and under 500mA Ic and have gotten 0,3volts Vcesat for 150mA and 1volt for 500mA. And how do you engineers do in such a case? Do you choose a value let's say close to Ic= 150mA and Ib=15mA and expect a Vcesat of about 0,3volts? I want to learn what to do in such cases, how to know roughly what Vcesat I will get at a given current.

 

[Jony130]

No single answer exist, It depends on an given application. Normally I assume that the Vce(sat) is around 0.2V for Ic<100mA and Ib = Ic/10 without even looking into data sheet. But for example if you build a single circuit just for hobby peruse you can use a typical value from figure 11. But if you want to design a circuit for a " spacecraft " then you must use a maximum value in your capitulations. For exampel you can assume Vce(sat) = 0.3V for Ic<150mA and Vce(sat) around 1V for Ic > 200mA.

 

[Genji Shimada]

No single answer exist, It depends on an given application. Normally I assume that the Vce(sat) is around 0.2V for Ic<100mA and Ib = Ic/10 without even looking into data sheet. But for example if you build a single circuit just for hobby peruse you can use a typical value from figure 11. But if you want to design a circuit for a " spacecraft " then you must use a maximum value in your capitulations. For exampel you can assume Vce(sat) = 0.3V for Ic<150mA and Vce(sat) around 1V for Ic > 200mA.

:D thanks, that helped a lot!

 

[rbelli1]

your capitulations

It's just one transistor. Not a whole robot army! ?

BoB