My electrician was asking if they are "electronic or magnetic" dimmer. I have no idea what that means.

Thanks!

Actual transfomrers can use a magnetic dimmer, while many of the small 'elecrtonic' transformers (actually AC-DC switching power supplies) can use a regular SCR type dimmer that you use for incandescent lights.

You need to check with the manufacturer to verify what type of dimmer the the electgronic transformer is designed for.

Pegasus lighting has small 60 W supplies (and even dual 60 watt units with two 60 W, 12 V outputs) that operate from regular SCR dummers.

Theuy sell just the supplies if you need them.

I found out that we need a low-voltage electronic dimmer.

That means the 'electronic' transformer you have is an older design.

It is realtively trivial to make a switching power supply that can handle a standard triac dimmer output for brightness control.

The manufacturers I know of that used to claim this have retracted the claim because of performance issues. Lutron engineers don't agree and UL seems to require that dimmers are correclty matched with load type. Dealing with electronic low voltage loads is one of the most infuriating things in lighting control. Unless the products are specifically tested by some manufacturer to work together it's best to test to see which parts will actually work before sticking ones neck out in a bid.