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Basically the question is, what it is?

Are those two emitters (meaning that part of semiconductor heavily doped)?

enter image description here

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  • \$\begingroup\$ There are multi emitter transistors too but their schematic symbol looks different. \$\endgroup\$
    – Uwe
    Commented Nov 5, 2022 at 18:43

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That's an IGBT. It has one collector and one emitter, but sometimes people draw an arrow on the collector too, perhaps because in truth the "collector" of an N-type IGBT is the emitter of an internal PNP BJT. (and no one makes P-type IGBTs, as far as I know, other than one from Toshiba that's no longer manufactured.)

The more common symbol for an IGBT is closer to this:

enter image description here

(image source)

You can think of an IGBT as a hybrid between a BJT and a MOSFET, with an insulated gate but the output characteristics of a bipolar device. This is what the symbol attempts to suggest: the gate separated from the channel as in a MOSFET, but the 45°-angled collector and emitter with an arrow on one as in a BJT.

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  • \$\begingroup\$ What does what unconnected pin represent? \$\endgroup\$
    – Qeeet
    Commented Nov 5, 2022 at 18:11
  • \$\begingroup\$ @Qeeet Sorry, I'm not sure I understand what you mean. \$\endgroup\$
    – Hearth
    Commented Nov 5, 2022 at 18:12
  • \$\begingroup\$ sorry, I've forggot to specify. What is the unconnected "wire" on the symbol I posted (between emitter and collector)? \$\endgroup\$
    – Qeeet
    Commented Nov 5, 2022 at 18:13
  • \$\begingroup\$ @Qeeet Oh! I'm not sure what that's meant to represent. The older symbols for IGBTs have it, while the ones you see today generally don't. \$\endgroup\$
    – Hearth
    Commented Nov 5, 2022 at 18:17
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    \$\begingroup\$ it seems it represents the n- region of the device, according to electrical4u.com/insulated-gate-bipolar-transistor-igbt figure: electrical4u.com/images/2017/february/… \$\endgroup\$
    – Qeeet
    Commented Nov 5, 2022 at 18:18

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