Characteristics of HP-IL Transformers?

[J-F Garnier]

(09-16-2020 09:06 PM)Dave Frederickson Wrote:  I've noticed that my PIL-Boxes are sensitive to my desk lamp being turned on or off. Besides adding isolation, will the pulse transformers make the PIL-Box more robust with regards to electromagnetic susceptibility?

(09-17-2020 12:22 AM)rprosperi Wrote:  Can you please explain the virtues of transformer coupling for us non-EE's in the audience? Put another way, why/how is this better (I presume you wouldn't bother to make this and announce it if it wasn't better) than a standard PIL-Box?

The transformer coupling ensures balanced signals: common mode (i.e. present on both wires) input transients are rejected - to some extend - and output signals have no common mode and generate less perturbations.
So it will probably improve the rejection of external EMI, although not at the same level than the HP design with the two-transformer input (see here). The capacitive coupling is quite limited on this respect.

But for the typical PIL-Box usage (personal use at home), it will not make a big difference.

There are two other PIL-Box limitations that are improved by the transformer coupling:
- you will be able to connect several PIL-Boxes/PIL-IO boards on the same loop,
- you can drive longer HP-IL cables.

Note that I released this information for possible DIY PIL-Box modification, I don't plan to make a new PIL-Box version.
My motivation was rather to demonstrate how to use HP-IL transformer coupling with modern components.

J-F