Register to reply

Rectifier efficiency

by dnyberg2
Tags: efficiency, rectifier
Share this thread:
dnyberg2
#1
Feb27-12, 03:13 PM
P: 69
Is it true that a full wave rectifier is more efficient than a half wave and if so why?
Phys.Org News Partner Engineering news on Phys.org
Researchers find security flaws in backscatter X-ray scanners
Virtual reality guides those whose memory is failing
Intelligent navigation system to personalise shopping trips
NUCENG
#2
Feb27-12, 03:44 PM
Sci Advisor
P: 916
Quote Quote by dnyberg2 View Post
Is it true that a full wave rectifier is more efficient than a half wave and if so why?
In simple terms, in the half-wave rectifier you throw away half of the AC signal by only usiing conduction in one polarity. The advantage is using fewer components (lower cost). The disadvantage is that for a given output voltage the diode must be able to conduct a larger load current (heat).
berkeman
#3
Feb27-12, 03:57 PM
Mentor
berkeman's Avatar
P: 40,932
Quote Quote by dnyberg2 View Post
Is it true that a full wave rectifier is more efficient than a half wave and if so why?
This is a trick question as stated, IMO. You need to give more context to the question, and give some definition of "efficiency".

vk6kro
#4
Feb27-12, 07:06 PM
Sci Advisor
P: 4,028
Rectifier efficiency

If you took efficiency as just power out divided by power in, the half wave rectifier would be slightly more efficient than a bridge rectifier (if we used a bridge rectifier) because the bridge rectifier has two diode voltage drops while the single diode just has one.
Otherwise, there is not a lot of difference because the input power to a half wave rectifier is supplied in half wave bursts and most of this power is delivered to the output.

However if they really meant "how effective are the two methods?", then the full wave bridge circuit would win every time.
The diodes of a bridge rectifier are only conducting half as much current as a half wave rectifier.
The peak current used for charging the filter capacitor is lower because pulses are delivered twice as often.
The filter capacitor can be smaller for the same hum-out level.


Register to reply

Related Discussions
PV Diagram Problem (ideal efficiency vs actual efficiency) Introductory Physics Homework 2
Isentropic efficiency vs polytropic efficiency of a gas turbine Aerospace Engineering 6
Polytropic efficiency vs isentropic efficiency? Mechanical Engineering 2