What does the out put wave form looks in a rectifier?

A rectifier allows current to flow only in one direction. In a half-wave rectifier circuit, an input wave which oscillates between positive and negative, will 'pass through' the positive portion of the wave, and when the input is negative will output zero. A full-wave rectifier circuit, is commonly configured with 4 rectifier diodes, which allow a positive wave to output when the input wave is negative.