Yes, the voltage in the DR is the same as in the US, when there is electricity. Receptacles are the same also. I bring small electrical devices (razor, CD player, etc.) from the US and they work just fine in the DR.
yes. it is "supposed" to be the same but in fact fluctuates sometimes to the low 80's and suddenly, BAM, it goes to 150volts. You can imagine the result on your electrical gears. A voltage regulator is a nice piece of hardware to have in this country.