Thinkpad AC adapters cross-compatibility?

[kadf88]

Are all Thinkpad AC adapters compatible with each other?
I tried plugging my X31 AC adapter into my A21p and it seemed to work,
but i didn't want to leave it plugged in that much because the X31 AC
adapter seems to output 3.5 amps while the A21p adapter outputs 4.5
amps...

does it hurt to cross-plug TP ac adapters? its just a hassle to unplug
and plug in a different adapter each time.

[Nolonemo]

My understanding is that if the AC adapter is underpowered for the TP, the battery will kick in to take up the slack. So you may experience a slow discharge of the battery while operating the TP, depending.

[jdhurst]

This question comes up over and over again in here. Please forget the myths and wrong answers.

Ohms law says volts x amps = power. An underpowered adapater can overheat, lower the voltage and has the capacity to damage the ThinkPad (not that it will). Using the wrong adapter for your ThinkPad is foolish in my opinion in that the proper adapter is cheap.
... JD Hurst