All About Circuits Forum half-wave rectifier with delay angle
 Register Blogs FAQ Members List Today's Posts Search Today's Posts Mark Forums Read

 Homework Help Stuck on a textbook question or coursework? Cramming for a test and need help understanding something? Post your questions and attempts here and let others help.

#1
10-03-2010, 11:12 PM
 notoriusjt2 Senior Member Join Date: Feb 2010 Posts: 209
half-wave rectifier with delay angle

it cant be this easy... what formula should I be using?
#2
10-03-2010, 11:44 PM
 R!f@@ Senior Member Join Date: Apr 2009 Location: Euphoria.., The One & Only {GMT +5} Posts: 7,055 Blog Entries: 3

Delay angle or not. A resistor will dissipate power according to the applied RMS Voltage
Formula is P=V^2/R
__________________
R!f@@
$\bullet$ Do not get angry and do not be harsh because you will never regret being kind $\bullet$

#3
10-03-2010, 11:54 PM
 notoriusjt2 Senior Member Join Date: Feb 2010 Posts: 209

in the book it gives me these equations....

Vm=Vpeak
then it says to use the P=Vrms^2/R

but it gives me no formulas that have anything to do with current.
are you sure thats still a valid answer?
#4
10-04-2010, 12:20 AM
 R!f@@ Senior Member Join Date: Apr 2009 Location: Euphoria.., The One & Only {GMT +5} Posts: 7,055 Blog Entries: 3

Quote:
 Originally Posted by notoriusjt2 in the book it gives me these equations.... Vm=Vpeak then it says to use the P=Vrms^2/R but it gives me no formulas that have anything to do with current. are you sure thats still a valid answer?
What does that equation look like.
Same one I gave u...forget the current. It is their to confuse newbies like you, and it is doing a pretty good job too.
__________________
R!f@@
$\bullet$ Do not get angry and do not be harsh because you will never regret being kind $\bullet$

#5
10-04-2010, 12:28 AM
 notoriusjt2 Senior Member Join Date: Feb 2010 Posts: 209

haha i gotcha, it is very confusing. that Vrms calculation takes into account for the delay angle. alpha=delay angle

so the delay angle has nothing to do with it? it doesnt even matter?
#6
10-04-2010, 12:31 AM
 R!f@@ Senior Member Join Date: Apr 2009 Location: Euphoria.., The One & Only {GMT +5} Posts: 7,055 Blog Entries: 3

Delay angle matters when the load is Reactive, Like Capacitive or Inductive.

Besides, ur Q, says average current.
Average values are not used for power calculation. Didn't u know that?
__________________
R!f@@
$\bullet$ Do not get angry and do not be harsh because you will never regret being kind $\bullet$

#7
10-04-2010, 02:13 AM
 notoriusjt2 Senior Member Join Date: Feb 2010 Posts: 209

i went with answer 'E' and it was incorrect

i know that delay angle needs to be accounted for somewhere
#8
10-04-2010, 03:01 AM
 R!f@@ Senior Member Join Date: Apr 2009 Location: Euphoria.., The One & Only {GMT +5} Posts: 7,055 Blog Entries: 3

shoooooot!!!. I missed the half wave rectifier part..
That was really clumsy of me...
Hold on, let me see
__________________
R!f@@
$\bullet$ Do not get angry and do not be harsh because you will never regret being kind $\bullet$

#9
10-04-2010, 03:12 AM
 R!f@@ Senior Member Join Date: Apr 2009 Location: Euphoria.., The One & Only {GMT +5} Posts: 7,055 Blog Entries: 3

Answer is way wrong. Since the AC is rectified we have to find the voltage seen by the load. which is lower than Vrms.
In the formula shows Vo, is any other formula given for Vo

{ed}
Is this q related to practical application. The delay angle is the SCR firing angle to rectify the AC. You have to find out Vo using a scope if this is practical based.
__________________
R!f@@
$\bullet$ Do not get angry and do not be harsh because you will never regret being kind $\bullet$

Last edited by R!f@@; 10-04-2010 at 03:40 AM.
#10
10-04-2010, 05:25 AM
 The Electrician Senior Member Join Date: Oct 2007 Posts: 1,746

You must first find the conduction interval that will give an average current of 2.5 amps into a 30Ω resistor.

Having found that conduction interval you then integrate instantaneous product of voltage and current over the conduction interval. That will give you the power absorbed by the resistor.

Alternatively, having found the relevant conduction interval, you could calculate the RMS value of that voltage coming out of the controlled rectifier, and use that value in the familiar formula P = E^2/R. The result is the same.

The first attached image shows the details. The second shows the RMS calculation mentioned in the paragraph above.
Attached Images
 Find SCR powr.png (23.3 KB, 16 views) Find SCR powr2.png (5.7 KB, 13 views)

 Tags angle, delay, halfwave, rectifier

 Similar Threads Thread Thread Starter Forum Replies Last Post darthfader Homework Help 1 12-19-2009 07:01 AM rperea General Electronics Chat 5 07-26-2009 09:07 PM Nuoz General Electronics Chat 4 02-26-2009 04:45 PM lsecrease General Electronics Chat 3 09-18-2008 05:12 PM strathy General Electronics Chat 19 03-27-2008 10:06 PM

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Electronics Forums     General Electronics Chat     The Projects Forum     Homework Help     Electronics Resources Software, Microcomputing, and Communications Forums     Programmer's Corner     Embedded Systems and Microcontrollers     Computing and Networks     Radio and Communications Circuits and Projects     The Completed Projects Collection Abstract Forums     Math     Physics     General Science All About Circuits Commmunity Forums     Off-Topic     The Flea Market     Feedback and Suggestions

All times are GMT. The time now is 11:04 AM.