Trinket works with USB but not with wall adapter My Adafruit 5V Trinket works fine when powered via USB connected to my computer (and the power going in to the Trinket is 5V), but if I use a 9V wall adapter with a microUSB adapter, it just powers on but doesn't seem to actually run the program on the Trinket.

Am I over powering the Trinket and sending too much voltage to everything? If that's the case, is there some way to decrease the voltage?
Yes, you are probably over-powering the trinket. The trinket expects 5V on the USB connector. However, it has an voltage regulator on board that can take up to 16V.

The BAT pin is connected to the voltage regulator and can take anywhere from 5.5V to 16V.