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For a transistor, parameters are β = 180 and VA = 150V, and it is biassed at ICQ = 2m A. If collector of the tansistor is connected to the base terminal, t hen small signal resistaance re = vce/ ic of this two-terminal device is ____ Ω .
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- 4.32
- 6.43
- 12.87
- None of the above
Correct Option: C
Since B– C junction is not reverse biased, therefore transistor continues to operate in the forwardactive-mode.
| r = | = | |||
| gm Vce | gm |
| rπ = | = 2.33 kΩ | |
| 2m |
| δm = | mA / mV = | = 77.2 mA / V | ||
| VT | 0.259 |
| ⇒ | = 12.95 | |
| gm |
| ro = | = | = 75 kΩ | ||
| ICQ | 2m |
∴ re = (2.33k) | | (12.95) | | (75k) = 12.87 Ω
