Which of the following represents the correct relationship between collector to emitter cutoff current (ICEO ) of a transistor and collector to base cut-off current (ICBO )? (Assume: ‘x’ is the CB current gain of the transistor)
By BYJU'S Exam Prep
Updated on: October 17th, 2023
(A) IECO = ICBO
(B) IECO = x ⋅ ICBO
(C) IECO = ICBO/(1 – x)
(D) IECO = ICBO/ (1 + x)
IECO = ICBO/(1 – x) represents the correct relationship between collector to emitter cutoff current (ICEO ) of a transistor and collector to base cut-off current (ICBO). Expression of Collector current in CE configuration: In CE configuration, the input current is IB and output current is IC.
As we know,
IE = IB + IC …. (1)
The expression for collector current in a CB arrangement is,
IC = xIE + ICBO …. (2)
Using equations (1) and (2),
IC = x (IB + IC ) + ICBO
IC (1 – x) = αIB + ICBO
IC = x/ 1-x IB + 1/1-x ICBO ….. (3)
In equation (3), it is apparent that if IB = 0, The collection current and the collector-to-emitter cut-off current will be equal.(ICEO).
This is written as ICEO, meaning Collector-Emitter current with a base open.
∴IECO = ICBO/(1 – x)
Summary:
Which of the following represents the correct relationship between collector to emitter cutoff current (ICEO ) of a transistor and collector to base cut-off current (ICBO )? (Assume: ‘x’ is the CB current gain of the transistor). (A) IECO = ICBO (B) IECO = x ⋅ ICBO (C) IECO = ICBO/(1 – x) (D) IECO = ICBO/ (1 + x)
IECO = ICBO/(1 – x) represents the correct relationship between the collector to emitter cutoff current (ICEO ) of a transistor and the collector to base cut-off current (ICBO).
