AC(Alternating Current): Alternating Current (AC) is a form of electrical current in which the flow of electrons changes direction periodically or in cycles.
Alternating current is the type of energy that travels down power lines and in typical home outlets.
DC( Direct Current): Electric charge carriers move or flow in only one direction when there is a direct current (DC) (which are usually electrons).
Despite the fact that the current's strength can change over time, its general motion is always in the same direction.
You may use an oscilloscope to determine whether a signal is AC or DC. If the output when the output wires are connected to the oscilloscope has a sinusoidal waveform, it is AC. An output of direct current (DC) is represented as a straight line.
By introducing a tiny current into the circuit and observing the voltage drop between specific circuit locations, multimeters can measure resistance. The resistance is then determined using Ohm's Law, , using the known current and the resulting voltage drop.
An AC voltage signal's frequency can also be determined using multimeters. A signal's frequency is determined by how many cycles recur on it every second. An example of frequency might be for a sine wave that repeats 10 cycles every second.