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I'm looking at triac datasheets, in particular this datasheet for BTA16 series triac. The "electrical characteristics" section is split into two parts: snubberless/logic level (3 quadrants) and standard (4 quadrants).

I have no idea what this is referring to. Are they different devices, as suggested by the column titles? Are they different operating modes? What is the difference?

Roman Starkov
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2 Answers2

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NXP has a good explanation as to what the differences between 3-quadrant and 4-quadrant triacs are.

Summary: a 3-quadrant triac cannot be turned on in the fourth quadrant (T2 negative, G positive) which is beneficial when dealing with inductive loads - ringing caused by sudden turn-off could potentially turn on a 4-quadrant triac, necessitating snubbers and other protection means to prevent spurious conduction.

Adam Lawrence
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    Link dead. Here's an alternative Link: http://datasheet.datasheetarchive.com/originals/distributors/Datasheets-NXP/DSANXP0100024.pdf – efox29 Nov 24 '16 at 06:27
  • Fixed. Yay for datasheetarchive, I don't think NXP / Nexperia carry any triacs at all any more... – Adam Lawrence Aug 03 '18 at 20:15
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3-Q Triacs don't operate in 4th quadrant i.e positive gate current and negative load current. Please see the link I ve shared http://en.wikipedia.org/wiki/File:TRIAC_Equivalent_Circuit.png. You will get an insight of the working of a TRIAC

Akash Vasisht
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