What output voltage does a half wave rectifier provide when 120VAC is input?

A half wave rectifier converts alternating current (AC) into direct current (DC) by allowing only one half of the AC waveform to pass through. When considering the input of 120VAC, it is important to understand that this value represents the root mean square (RMS) voltage of the AC signal.

To find the peak voltage of the AC input, which is necessary for determining the output voltage of the half wave rectifier, you can use the formula:

Peak Voltage (Vp) = RMS Voltage (Vrms) × √2.

For 120VAC, calculating the peak voltage gives:

Vp = 120V × √2 ≈ 169.7V.

In a half wave rectifier, the output DC voltage (Vdc) can also be approximated as the peak voltage minus the forward voltage drop of the diode. The forward voltage drop is typically around 0.7V for silicon diodes but can vary based on the type of diode used.

Hence, after rectification, the effective DC output voltage would be around half of the peak voltage from the AC input due to the nature of half wave rectification:

Vdc = (Vp / π) ≈ (169.7V / π) ≈