Why is gate drive transformer numbered clockwise?

[Faringdon]

Hi,
Do you know why this is numbered clockwise?

https://www.mouser.co.uk/datasheet/2/447/datasheet_p883_1644367525-2903056.pdf

[TimFox]

It depends on how you look at it …

[MarkT]

Because the datasheet says so, simple as.

[TimFox]

A bit of history relevant to IC packages, but not necessarily to transformers.
The pin numbers for vacuum tubes were always numbered clockwise from the bottom, since the wires were connected to a socket on the opposite side of the mounting plate, and the voltages were probed from that side.
This convention persisted for DIP ICs and other semiconductors, even though they are usually visualized and probed from the top, where the pin numbering is therefore counter-clockwise.

[jonpaul]

these predate ICs, SCR, thyratron, IGBT pulse trsf.

There is really no std on the trsf footprint, some bobbins origianted in Japan,

Jon

[Bud]

Minicircuits has a part with a dot marking the last pin, not first pin.

[langwadt]

Minicircuits has a part with a dot marking the last pin, not first pin.

I remember a USB controller something like a qfp with pin one in the middle of a side instead of the corner, same IC in a tsop had normal numbering, so using the same symbol and just changing the footprint to a qfp with normal pinnumbering would mean all the pin were of by half a side ...

[MarkT]

I think it just comes down to the simple rule - always read the datasheet and assume nothing.

[tggzzz]

I think it just comes down to the simple rule - always read the datasheet and assume nothing.

Read and understand the datasheet/manual. And also read and understand what it doesn't say.

Some people (no names monikers, no pack drill) will find that task impractical

[newto]

I think it just comes down to the simple rule - always read the datasheet and assume nothing.

Read and understand the datasheet/manual. And also read and understand what it doesn't say.

Some people (no names monikers, no pack drill) will find that task impractical

The understanding is very important. Currently working on a replacement for a product that was designed in the 90s by people that just copied the example circuits out the datasheets with no real understanding on how they worked. It's a miracle the whole thing *did* work, but it's finicky to get working and adjust, and if you ever let the super capacitor attached to the RTC drain, you need to do a mystical ritual of button pressing, cable removal, and battery replacement to get the thing to boot again. And why did it have a supercap on the RTC in the 90s? Because the button cell they originally designed for it would mysteriously drain over a few weeks, so they just copied the supercap example from the datasheet and bodged it on with a daughter board, and never tried to figure out the actual problem.