Question

Explain what would be observed if the sliding contact were raised from the 0V end to the 3V end of the potentiometer.

Answer 1

First, this is an NPN transistor shown with equal negative potentials across its base and emitter. Therefore, it is currently in the "off" position. As you slide the contact upward the base of the transistor will become more positive than the emitter which will eventually turn the transistor "on" allowing current to flow from its emitter to its collector.

Answer 2

So the bulb will light up? And would it go off after some time? @stormfire1

Answer 3

The bulb will light up and stay lit until the slider is moved back down.

Answer 4

As long as the base is 0.6V higher than the emitter (since it's an NPN transistor), the transistor will conduct current from emitter to collector and to the light bulb...so it will be lit.

Answer 5

Ok. You said the current would flow from emitter to collector. But my book says otherwise. It says it flows from collector to emitter. >_<

Answer 6

It really depends on how you're being taught. In one convention current flows from positive to negative and in the other, it flows from negative to positive. It doesn't really matter in 99% of applications because as long as you stick with one convention, everything will work out.

Answer 7

It looks like your book is teaching that current flows from + to -...which is fine. Go with current flowing from collector to emitter in your answer.

Answer 8

Ok. Thank you so much for helping me out! :)

Answer 9

My pleasure