120 v comes out of a wall outlet.
120 v comes out of a wall outlet.
what voltage comes out of a wall outlet?
120 v
use of an external power supply allows portability of equipment powered either by mains or battery without the added bulk of internal power components, and makes it unnecessary to produce equipment for use only with a specified power source; the same device can be powered from 120 vac or 230 vac mains, vehicle or aircraft battery by using a different adapter. another advantage of these designs can be increased safety; since the hazardous 120 or 240 volt mains power is transformed to a lower, safer voltage at the wall outlet and the appliance that is handled by the user is powered by this lower voltage.
ac adapter
so at dc (0 hz), the capacitor voltage is in phase with the signal voltage while the resistor voltage leads it by 90°. as frequency increases, the capacitor voltage comes to have a 90° lag relative to the signal and the resistor voltage comes to be in-phase with the signal.









































section::::series circuit.:time-domain considerations.









































the most straightforward way to derive the time domain behaviour is to use the laplace transforms of the expressions for and given above. this effectively transforms . assuming a step input (i.e. before and then afterwards):









































partial fractions expansions and the inverse laplace transform yield:
rc circuit