Output of transformer
There's no voltage regulation in a (normal) transformer; voltage regulation would imply the voltage wasn't primarily load-dependent, but it is. A transformer has a (complex) source impedance, and so has the source it's connected to, and you can pretty directly see how that's not a regulated system.
You'll need to do very specific things to incorporate regulation into a transformer; wikipedia &quot;voltage regulator&quot; has a section on AC voltage regulation, and your transformer isn't a regulator.