Press play and view how power is rectified from AC to DC. LEDs are still diodes and will work as rectifier diodes at low voltage. Notice how on each AC wave, only 2 rectifying LEDs light in an alternating fashion, this is because current can only flow through the forward biased LEDs during each half wave. However, notice the top LED light on both halves of the wave? This is because this led is powered from the rectified positive and negative output of the rectifier, therefore, each AC half wave is rectified into direct forward current. This is a full wave rectifier. You can also add a smoothing capacitor across the output to fill in the tiny pauses between AC polarity shifts.
