rectification questions

Thread Starter

ece_geki

Joined Jul 5, 2007
2
hw given to me...kinda hard to find on the net...

1.) discuss the importance of rectification.

2.)define ripple factor.

3.)discuss the importance of the bleeder resistor.

4.) discuss the effect and importance of the shunt capacitor.

5.) discuss the effect and importance if a RC filter.

6.) discuss briefly the applications of half-wave rectifiers.

thanks in advance!
 

bloguetronica

Joined Apr 27, 2007
1,372
The purpose of the bleeder resistor is to discharge the filter capacitor, since we are talking about power supplies. If a capacitor is left charged, its lifespan might decrease, hence the usefulness of the bleeder resistor.
Of course this is the only answer I will give to you, since the other are searcheable. Not very hard if you try google. I just googled for "ripple factor" and found 19100 entries.

I suggest the following:
http://en.wikipedia.org/wiki/Rectifier
http://en.wikipedia.org/wiki/Ripple_(electrical)

You will learn more if you search by yourself. Don't expect others to solve your assignments. The best we can do is to help case you have any doubt.
 

JoeJester

Joined Apr 26, 2005
4,259
If a capacitor is left charged, its lifespan might decrease ...
Interesting statement. Care to cite a study or reference?

The bleeders are in there for safety ... to provide a discharge path for the charged capacitors. In some instances, they are not connected to the capacitors until power is removed and the equipment is open.
 

bloguetronica

Joined Apr 27, 2007
1,372
Interesting statement. Care to cite a study or reference?

The bleeders are in there for safety ... to provide a discharge path for the charged capacitors. In some instances, they are not connected to the capacitors until power is removed and the equipment is open.
Sorry, forgot to mention that I was talking about electrolytic capacitors. In all other capacitors, the lifespan won't decrease, of course. The reason why that happens with electrolytic capacitors has to do with corrosion, if I recall.
 

JoeJester

Joined Apr 26, 2005
4,259
Sounds reasonable. I just didn't find anything on the web [other than your statement] concerning the decrease lifespan attributed to the bleeder resistor and the discharge cycle.

I guess I'll look some more, to see if I can nail down a reference or two.
 

Thread Starter

ece_geki

Joined Jul 5, 2007
2
thanks a lot guys...the reason why i needed the answers soon because the report was due the next day...thanks again..
 
Hallo




There's one thing I don't quite understand about this schematic
i need to know what the capacitors in parallel with diodes (0.01uF)
is for
they have very small capacitance
so
what is their effect on circuit
 

crutschow

Joined Mar 14, 2008
24,710
Those small capacitors are to minimize the EMI from the rapid change in current as the diode goes from conducting to non-conducting. This EMI can sometimes be heard as a high-frequency buzz in electronic equipment.
 
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