Half wave rectifier, Average load current (ILdc), Average load voltage (VLdc), RMS load current(IL rms), RMS load voltage (VL rms),Ripple factor, Voltage regulation, Rectification efficiency and TUF of HWR. Advantage and Disadvantage of HWR
Half Wave Rectifier
For positive voltages (voltage drops in the
direction the diode points), the diode offers
no resistance.
For negative voltages (voltage rises in the
direction the diode points), a diode offers
infinite resistance. That is, it acts as though
there is no connection where the diode is.
Analysis of HWR
Average load current (ILdc)
Average load voltage (VLdc)
RMS load current(IL rms)
RMS load voltage (VL rms)
Ripple factor
Voltage regulation
Rectification efficiency and TUF.
Vdc
Area under the curve over full cycle base
= Vm
= 0.318 Vm
Idc
RL
= Vm
π.RL
= Im.π
=0.318 Im
Rectifier characteristics
1.Voltage regulation-
% R= Vnoload – Vload * 100
Vload
2. Efficiency :
η = Pdc
Pac
3.Peak inverse voltage : (PIV)
The maximum voltage which can be subjected to the diode in reverse bias in rectifier circuit is called Peak inverse voltage.
4. Ripple factor :
γ=RMS value of ac component
Avg or dc component
γ = Iac
Idc
5. Transformer utilization factor (TUF):
TUF= DC power delivered to load
AC power delivered of xformer
= I2dc RL
Irms V rms
γ = Iac
Idc
= I2m / 2 RL
Im /2 Vrms
= Im * 2 * RL * 2
2 * Vm
= 4 = 0.287
2
Disadvantages
Ripple factor is high. Ripple factor is 1.21,thus output contains lots of varying components.
Low rectification efficiency. The max theoretical efficiency is 40.6 % but practically the value will
be less.
The rectification is done only for half cycle.
Load X-former utilization factor is 0.287.
Larger filter components are required.
The half-wave rectifier “wastes” part of the
input signal, since the negative lobes of a
sine wave are just clipped off.
It is possible to use both the positive and negative lobes with a full-wave bridge rectifier.