What Should I Look at to Find Vce(sat) for PN2222A Transistor?

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The discussion centers on understanding the Vce(sat) values for the PN2222A transistor, noting discrepancies between the datasheet and actual performance graphs. It highlights that Vce(sat) is approximately 0.3 volts at 150mA and can reach 1 volt at 500mA, causing confusion about expected values at various collector currents. Participants emphasize that the choice of Vce(sat) depends on the application, suggesting typical values for hobby projects but recommending maximum values for critical designs, such as in spacecraft. The consensus is that while typical values can be used for less critical applications, careful consideration is necessary for more demanding scenarios. Overall, understanding the context and application is crucial for determining appropriate Vce(sat) values.
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On this datasheet of PN2222A bipolar transistor
Screenshot_2016-08-14-21-06-06.png


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?
 

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And here's the graph
Screenshot_2016-08-14-21-06-21.png
 
Jony130 said:
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.
Screenshot_2016-08-14-22-04-02.png
 
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.
 
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Jony130 said:
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!
 
Jony130 said:
your capitulations

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

BoB
 
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