Average output voltage of half wave rectifier and formula for calculating RMS output voltage. Firstly we need to understand the output waveform of this rectifier circuit.
1. The output waveform of the half wave rectifier
We all know that diodes only allow current to flow in one direction. And it blocks the current in the reverse direction. The most common application of diodes is to convert AC voltage to DC. This process is called rectification. A rectifier circuit that uses only one diode is called half-wave rectifier.
The output waveform of the half-wave rectifier
Half wave rectifier circuit using only one diode in series with supply voltage. The voltage after rectification is not pure DC. It is a pulsating DC.
+ In the positive half-cycle (Vin > 0): The diode is forward biased. The diode acts as a closed switch. Then the resistor will be connected in parallel with the supply voltage, so the output voltage is equal to the supply voltage.
=> t: 0 – π Then Vout = Vin > 0
+ In the negative half-cycle (Vin < 0): The diode is reverse biased. Because The diode acts as an open switch, no current flows in the circuit. The output voltage is zero volts during the negative half period.
=> t: π – 2π Then Vin < 0, Vout = 0
2. Average output voltage of half wave rectifier
Assume that supply voltage has the equation: Vin = Umax.Sin(wt) = 310Sin(100 πt).
+ Formula to calculate the average output voltage of half wave rectifier:
+ Formula to calculate average output current:
Because the circuit uses a resistive load. So average output current of half wave rectifier is:
Io = Uo/R
3. Calculate Root Mean Square (RMS) value
+ Root Mean Square voltage formula:
+ Root Mean Square current formula:
IRMS = URMS/R
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>>> See also: Calculate the RMS and Average value of Half wave Rectifier and Full wave rectifier