2
\$\begingroup\$

I am new to electronics and this question might seem silly.

I do not understand why in the transistor below current seems to flow from collector to emitter, because based on what I have read, I'd say this is a PNP transistor — isn't current meant to flow from emitter to collector in a PNP transistor?

Also, isn't a small current meant to go from the emitter into the base? It does not seem like it's happening here.

Schematic

\$\endgroup\$

1 Answer 1

Reset to default
2
\$\begingroup\$

Yes, it's supposed to, and yes, it does.

That is, the emitter is at -14 volts, and the collector is at-15.5 volts, so the emitter is 1.5 volts positive with respect to the collector. So current flows into the emitter and thence to the collector.

\$\endgroup\$
10
  • \$\begingroup\$ thank you! i am still confused though... to to me it seems like the current passes from collector to emitter, then to the rest of the circuit (and I thought the rule was that it should go the other way around)....am I wrong? thanks again :) \$\endgroup\$
    – vneg
    May 13, 2016 at 0:19
  • \$\begingroup\$ @vneg - Current goes from collector to emitter for NPN. For PNP it's the other way. Look at the direction of the arrow on the emitter symbol for each type. \$\endgroup\$
    – WhatRoughBeast
    May 13, 2016 at 1:36
  • \$\begingroup\$ so are you saying that the current goes from the emitter (with arrow, at -14 volts) to collector (no arrow, -15.5)? I find it puzzling, as the current goes from the emitter to the rest of the circuit, rather than coming into the emitter when I look at the whole schematic.... \$\endgroup\$
    – vneg
    May 13, 2016 at 1:53
  • \$\begingroup\$ could you please have a look here and tell me what you think? I think in this situation we are having an emitter follower/ common collector. radio-electronics.com/info/circuits/transistor/… "For both NPN and PNP circuits, it can be seen that for the emitter follower, common collector amplifier circuit, the input is applied to the base, and the output is taken from the emitter. The common terminal for both circuits is the collector." \$\endgroup\$
    – vneg
    May 13, 2016 at 1:56
  • \$\begingroup\$ Current follows the arrows, from +15V to +14V and from -14V to -15V, the current flows from the more positive terminal to the more negative terminal (well using conventional current anyway, but lets not get into that) \$\endgroup\$
    – Sam
    May 13, 2016 at 2:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.