Rectifier, with dc as input. what happens??

[settra]

hey guys. i was wandering. what if instead of AC in a rectifier, i input DC??
i have tried with one rectifier i got from an old PSU, and it seems to just give DC output.

the reason i am asking this is : i have a line that is supposed to have only DC on it. but it very well has some AC as well (ripple, from car alternator). if i use a rectifier, will it convert the AC of the line , to DC as well??
also, how many amperes could this hold??

 

[audioguru]

If you use a HUGE capacitor following the rectifier then it can let the rectifier peak detect the peaks of the ripple and produce fairly smooth DC.
A voltage regulator will completely eliminate the ripple but the DC will be a little lower than without it.

 

[jpanhalt]

Another practical use of a rectifier (full wave) on DC to polarity protection. That can be useful in battery operated devices in which someone may insert the batteries incorrectly.

John

 

[Willen]

how many amperes could this hold??

This will depend on diodes' maximum capacity for current.

I guessed we don't have to worry about '+' and '-' polarity of battery if we use Bridge rectifiers. We can connect '+-' or '-+' anything to bridge rec. but I think only two diodes which are conducting might get hot, isn't it?

 

[MrAl]

Hi,

Yes the diodes will dissipate power and add to the losses. For a bridge that means two diode drops.

 

[alec_t]

If you are asking whether simply applying a DC voltage with ripple on it to a rectifier will remove the ripple the answer is 'no'.