Originally Posted by
reclusive46
They all vary in size, my debit UK debit card is very small but I find that My Amex and Capital One both have very big chips. I find contactless cards tend to have the big ones.
I found that interesting so I Googled why dual-interface cards might have "the big ones" (that is ones with contact pads C4 and C8 - unused optional pads). I very quickly found that on dual interface cards (at least on many), pads C4 and C8 (otherwise unused) function as an antenna connector.
Question answered, it seems. US cards are never ever dual interface (there are no contactless EMV cards on the US market), thus why most don't have C4/C8. Interesting insight.