Electronics and Communication Engineering - Analog Electronics - Discussion

14. 

In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit

[A]. all calculations done earlier have to be repeated
[B]. replace all calculated voltages by reverse values
[C]. replace all calculated currents by reverse values
[D]. replace all calculated voltages and currents by reverse values

Answer: Option D

Explanation:

All voltages and currents have reverse polarity.


Shakti said: (Jul 21, 2014)  
How please demonstrate?

Dipanjan said: (Feb 7, 2015)  
@Shakti.

For that you need to understand the differences between NPN and PNP transistors.

First of all, in NPN, current flows from collector to emitter but in case of PNP, current flows from emitter to collector.

Another important difference is with respect to base voltage (with respect to gnd). If the voltage at the base is increased in NPN, rate of current flow increases simultaneously but decreases in case of PNP.

Correct me if I'm wrong.

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