I'm a bit confused about the saturation of a transistor. Let's say I have a pn2222a NPN transistor. Its Hfe value is 100. My base voltage is 5 Volts and Vbe voltage drop is 0.6 volts. I want to draw 20mA from collector at most.

So far so good. Now I make the base resistor calculation simply by the following formula;

(5-0.6)/(20mA/100) = 22k ohm

Now, this is the maximum base resistor for putting 20mA to collector. Anything under this would put more current. Yet my load would draw the necessary amount of current given that it has a current limiting resistor. (Let's say an LED with a resistor)

The thing confusing me is, how I can determine whether my transistor is saturated.

So far so good. Now I make the base resistor calculation simply by the following formula;

(5-0.6)/(20mA/100) = 22k ohm

Now, this is the maximum base resistor for putting 20mA to collector. Anything under this would put more current. Yet my load would draw the necessary amount of current given that it has a current limiting resistor. (Let's say an LED with a resistor)

The thing confusing me is, how I can determine whether my transistor is saturated.

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