In article >,
"TeGGeR®" > wrote:

> Jim Yanik .> wrote in
> :
>
> > "TeGGeR®" > wrote in
> > :
> >
> >> Randolph > wrote in
> >> :
> >>
> >>> The
> >>> data sheet shows the diode between emitter and collector.
> >>
> >>
> >> So then it wouldn't make much sense to try and show it.
> >>
> >> Randolph, I'm having trouble understanding the current path through
> >> the transistor. I found this page:
> >> http://nobelprize.org/physics/educat...nction/thegame.
> >> h tml
> >>
> >> It helps me understand more, but I don't get which way the current
> >> goes through the base electrode. I have a suspicion that my diagrams
> >> show the current going the wrong way through the transistor.
> >> http://www.tegger.com/hondafaq/ignit...ion/index.html
> >>
> >>
> >>
> >
> > There's two current paths;the B-E path and the C-E path(main path).
> > Current flows the opposite direction of the emitter arrow,for both
> > base and collector currents.
> >
>
>
> I'm having trouble getting my mind around this.
>
> I am aware that "flow" is _commonly_ considered to be from the positive to
> negative terminals of the battery, but the electrons themselves go in the
> OTHER direction.

Most materials have an electron flow, which goes from negative to
positive. I've heard that some materials can have a proton flow. Both
may exist in a vacuum.

Current flow arrows on diagrams go from positive to negative.

Bipolar transistors are current amplifiers. When a current flows
through the base-emitter diode junction, a stronger current is allowed
to flow from the collector to the emitter. The C-E junction is .2 to .4
volts when the B-E junction is saturated (~.65 V). The current gain for
a power transistor is usually 10 to 100. Darlington pairs have that
gain squared. Gains are not at all consistent so they're usually
specified as a range.

MOSFETs are tiny voltage controlled amplifiers. Absolutely zero static
current is required to turn them on or off; just the capacitance
current. Because of their infinite current gain, millions may be
paralleled on a single chip to satisfy any current load. Their voltage
gain is very low - a typical gate threshold voltage is 4V and a typical
gate saturation voltage is 10V. There's no voltage drop between the
source and drain, only resistance. High voltage capability makes each
MOSFET junction larger and dramatically increases resistance.

IGBTs are similar to bipolar transistors but with an insulated gate like
a MOSFET. They have the high voltage capacity of bipolars but need no
driving current like a MOSFET. They're very slow so they're usually
limited to controlling industrial motors. (Honda hybrid cars use them
for their motors.)


> http://www.tegger.com/hondafaq/ignit...ion/index.html
> http://www.tegger.com/hondafaq/ignit...adigniter.html
> On these two pages, is the current flow through the transistors correctly
> depicted? Nobody has answered that question yet.