I am supposed to calculate the diode current when the switch is closed and also determine what region the transistor is working in when the LED diode is conducting current.
The way I tought to go about this problem is to first calculate the collector voltage so I can determine which region the transistor is working in.
First I need the base current:
Ib = 14.3 V÷15k = 0.95 mA
Now I can calculate the collector current using β:
Ic = Ib*β = 95 mA
I am not sure when I am allowed to use this formula because I read somewhere that this formula only stands true when the transistor is working in active region. I don't understand when I can use it and how I should know if the transistor is in active region. If someone could explain this it would be very helpfull.
Now I can calculate Vc:
Vc = 15 V - 2 V - Ic * 1.5k = -129.5 V
The 2 V voltage drop comes from Vd (diode
breakthrough voltage).
I do not how to procced from here. What does this tell me? My best assumption would be that the transistor is working in saturated region but that is just a wild guess and I don't even know how to use that information.
The way I tought to go about this problem is to first calculate the collector voltage so I can determine which region the transistor is working in.
First I need the base current:
Ib = 14.3 V÷15k = 0.95 mA
Now I can calculate the collector current using β:
Ic = Ib*β = 95 mA
I am not sure when I am allowed to use this formula because I read somewhere that this formula only stands true when the transistor is working in active region. I don't understand when I can use it and how I should know if the transistor is in active region. If someone could explain this it would be very helpfull.
Now I can calculate Vc:
Vc = 15 V - 2 V - Ic * 1.5k = -129.5 V
The 2 V voltage drop comes from Vd (diode
breakthrough voltage).
I do not how to procced from here. What does this tell me? My best assumption would be that the transistor is working in saturated region but that is just a wild guess and I don't even know how to use that information.
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