Question

Given that for a transistor, hie = 1100Ω, hfe = 50, hre = 2*10^-4 and hoe = 2μΩ^-1. Find CB h-parameters.

(a) hfb = 1, hib = 22, hob = 3μΩ^-1, hrb = -1.5×10^-4

(b) hfb = -0.98, hib = -21.56, hob = 0.03μΩ^-1, hrb = 1.5×10^-4

(c) hfb = -0.98, hib = 21.56, hob = 0.03μΩ^-1, hrb = -1.5×10^-4

(d) hfb = 1, hib = -21.56, hob = 0.03μΩ^-1, hrb = -2×10^-4

I had been asked this question in my homework.

My doubt stems from Hybrid Equivalent Model in chapter Transistor Biasing and Low Frequencies of Analog Circuits

Answer 1

Right option is (c) hfb = -0.98, hib = 21.56, hob = 0.03μΩ^-1, hrb = -1.5×10^-4

Explanation: hfb = -hfe/(1+hfe) = -50/51 = -0.98

hib = hie/(1+hfe) = 21.56Ω

hob = hoe/(1+hfe) = 0.03 μΩ^-1

hrb = (hiehoe/1+hfe) – hre = -1.5×10^-4.