Input resistance of a common emitter transistor of the order of

The correct answer is option 2):(1 ΚΩ)

Concept:

• In common emitter configuration, the emitter is common to both the base and collector. The emitter-base junction is always forward-biased as the positive terminal of the battery is connected to the p-side of the transistor and the negative terminal of the battery is connected to the n-side of the transistor.

• The input impedance is typically around 1kΩ, although this can vary considerably according to the circuit values and conditions. The low input impedance results from the fact that the input is applied across the base and emitter where there is a forward-biased junction, Also the output impedance can be relatively high. Again this varies considerably on the electronic component values chosen and current levels permitted. The output impedance may be as high as 10kΩ or possibly more

• However, if the current drain allows higher current levels to be drawn, the output impedance can be reduced considerably. The level of resistance or impedance comes from the output taken from the collector where there is a reverse-biased junction.