"Finger Tap" animation?

Hey people! Trying to mock up a SIMPLE "touch screen" animation : a little ripple,-type-thing, super simple that shows a "touch" has happened on the screen.

I don't have MOTION, and was wondering if there's an easy-ish way to simulate this?

Doesn't have to be fancy. Any ideas are welcome!

tx

Add from the Generators a circle
Keyframe within a few frames its size and its transparency…..

… very unfancy ;but all-done in fcpx

I vaguely remember a much nicer plugin, creating such a ‘ping!’…. dig in fcp.co’s morgue of free effects, or the usual suspects…

I poked around. but didn't see much, so I tried to use the generator to make a growing little circle and it worked! Well, sat least good enough for my purposes.

The PROBLEM now is that once I enter the iPhone pixel dimensions (750 x 1334) the generator circle is ALWAYS cut off on the sides! I even tried to make a little tiny circle in another project and then copy/paste it in…but it STILL gets cropped off on the sides.

I spent an hour last night trying to deal with that. I don't have MOTION, and would love to NOT have to buy it, lol, at least not yet.

Any ideas on how to get an actual ROUND circle!?