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tadm123
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Homework Statement
We have a transistor with RB, RE and A LED being a GaAs Light-emitting Diode (LED with a forward voltage of approximately 1.5V.
Values for RB= 2K, Vs-offset=5, Vs-amplitude=4, V-frequency= 1KHz, let β=100
what is the value of the emitter resistor for which the LED sinusoidal current will
have an offset level of I=27 mA?
Use two methods to create such a current:
Method A: Keep RE constant (say 200Ω) and vary VOFF of the VSIN source.
Method B: Keep VOFF constant (say 5V) and vary RE.
In each case, once you set the DC current to 27mA, check the sinusoidal collector current
iC(t), and make sure that it doesn’t get clipped. If it does, reduce VAMPL of the VSIN
source, from 4V to a lower level, but as large as you can make it to keep the LED
currents from clipping
Homework Equations
The Attempt at a Solution
By I offset do they mean the value of I current (in collector)?
If it is then I used the formula for current in emitter
Ie= (Vin-Vbe)/ (Re- Rb/β+1)
plugging in values and solving for Re I get => Re= 139.46Ω.
I guess this is more of a PSPICe problem but I just want to make sure if by the current offset they meant the value of the current.