Hybrid π model- Inversely related parameters with input conductance

Q.  Which among the below specified parameters exhibit inverse relationship with an input conductance of hybrid π model?
- Published on 23 Sep 15

a. Temperature at constant hfe
b. Current at constant hfe
c. Voltage at constant hre
d. Resistivity at constant hre

ANSWER: Temperature at constant hfe

Related Content

 

    Discussion

  • Satyawati   -Posted on 30 Sep 15
    Referring to the analysis of hybrid π-model at low frequencies and the equation of short-circuit current gain, the resistance across the base-emitter junction is given by,

    r'be = hfe VT / |Ic|

    This expression concludes that, r'be is directly proportional to temperature & inversely proportional to current only if hfe is constant over a certain range of current.

    Since the input conductance (g'be) is reciprocal to the resistance (r'be), it can be expressed as,

    g'be = 1 / r'be

    g'be = |Ic| / hfe VT

    However, the equation of input conductance at base-emitter junction implies that it has inverse relationship with the temperature (VT) while it is directly proportional to current, provided that 'hfe' is constant.

➨ Post your comment / Share knowledge


Enter the code shown above:

(Note: If you cannot read the numbers in the above image, reload the page to generate a new one.)
▲