If an npn transistor has a beta cut-off frequency fB of

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If an npn transistor has a beta cut-off frequency f_B of 1MHz, and emitter short circuit low frequency current gain β₀ of 200, then unity gain frequency f_T and alpha cut off frequency f_α respectively are

1. 200 MHz, 201 MHz
2. 200 MHz, 199 MHz
3. 199 MHz, 200 MHz
4. 201 MHz, 200 MHz

Correct Option: A

f _T = β₀ × f_β = (200) × 1 MHz = 200 MHz

and f_α =	f_β	=	f_β
	1 - α		1 -	β
				1 + β

= f _β (β+ 1) = 10⁶ (200 + 1) 10⁶ × 201 = 201 MHz