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The long time question of hfe..... well, hfe depends on the aplication u are using the transirtor for. eg: if you are designing to work on saturation you wanna try an hfe of 10 or less to asure the transitor keeps in that region, this hfe u desing when polarized, witch i dont think is your case.
The other way to decide on a hfe is to set the Ic current, if you see the datasheet he typical hfe is 60, if you look further down there is a graphic of hfe vs Ic for and stasific Vce, in this case is 10v, there u can aproximate the hfe of the transistor.
If you want the out of circuit hfe, well, u can use a multitester with hfe measure, they are kinda common thought not very reliable cause hfe varies a lot due to many factors.
Very thanks u !! but I think if I wanna designing to work on saturation I should use an hfe of larger not less to asure the transitor keeps in that region.
If you want to know the precise value of needed base current for your application,just connect the transistor with the collector load and voltage and then increase the base current until Vce reaches the value you need (e.g. 0.2V).A base resistor 5koms and a potentiometer (1Kohms) between Vcc and GND to regulate the base current will do.
Do not oversaturate if you need fast switching!
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