J

#### Jacky Luk

- Jan 1, 1970

- 0

The early voltage is 60V in a common-emitter configuration for a npn bipolar

transistor. With Vbe = 0.65V and Vce = 1V collector current = 1.0mA, find

the collector current when Vbe = 0.67V and Vce = 9V

If i use the geometry thoery to calculate this,

I think i can approach to yielding the answer of this question. However when

Vbe's are different, the slope of these two curves are virtually different,

consider the

Slope of the device curve when Vbe = 0.65V

Vbe = 1mA / 60V + 1V where I would think of something similar to Vbe (when

0.67V) = Ic / 60V + 9V. Does the question offer too few or too many

parameters in solving the question?

but as stated in my book, using equation Ie = Ise * e ^ K * Vbe where K is

about 40V, I can yield the answer to be Ic = 1mA * Exp (40V -1 * 0.67V -

0.65V)

which is according to the first equation which states in my reference " it

shows that 10mV Increments correspond to increases in Ie and Ic by a factor

of exp (40V-1 * 0.01V) ".... then I feel the question is offering two many

parameters where some of them are not used???

Please help

Jack