Question

Collector current (Ic) reaches zero when

(a) Vce = Vt ln (Isc/I)

(b) Vt = Vce ln (Isc/I)

(c) Vce = Vt ln (I/Isc)

(d) Vce = Vt ln (Isc + I/I)

The question was asked during a job interview.

I need to ask this question from BJTs Current-Voltage Characteristics in section Bipolar Junction Triodes (BJTs) of Electronic Devices & Circuits

Answer 1

Correct answer is (a) Vce = Vt ln (Isc/I)

Easiest explanation: Ic = Is exp (Vbe/Vt) – Isc exp(Vbc/Vt). In this expression put ic = 0 and simplify.