From: John Popelish
Organization: This space not available for advertising.
X-Mailer: Mozilla 4.7 [en] (Win98; U)
Subject: Re: Inductor used in 110v to 15v
Date: Fri, 29 Nov 2002 02:43:15 GMT
NNTP-Posting-Date: Thu, 28 Nov 2002 21:43:15 EST
> "John Popelish" wrote in message
> > Did you ... ebay?
> No, but just out of curiosity, what are you going to use yours for? (Not important but if you feel like sharing...)
I just got one to add to my collection. :)
I don't have any specific plans for it, yet.
> > the 75HQ035 ... from Digikey.
> This is of great help to me. I really appreciate your post. Do you endlessly search Digikey until you are successful or do you
> have a more efficient method for finding the parts you need?
I have their paper catalog, which has things grouped into sections,
with short form specs for most items. There are a couple pages of
just schottky diodes, and many more of PN junction diodes in all
> Will my voltage drop after going through the diodes? If so, by how much or what is the formula to determine how much voltage drops.
Each diode will waste about a half volt, and two conduct in series in
the bridge configuration, so you will lose about a volt (and 1/13th of
the power that gets dumped into the heat sink).
> BTW, do you know what a full wave bridge rectifier is? I have a project book that mentions this type of rectifier and I can not
> find it on Digikey. They have half-bridge rectifiers but I am unclear on whether or not this will work.
A bridge rectifier is 4 diodes packed in one device with 4 terminals.
Digikey sells bridges for up to 35 amps, so if you don't need the full
output of your transformer, you could use one of those and save most
of the diode cost. A 35 amp, 50 volt bridge (GBPC35005) costs about
$5. For the same price, you can also get 100 to 1000 volt versions,
so you should probably get one of these to give you more margin on the
voltage rating. But these are made with PN diodes, which waste about
1 volt each, so produce twice the heat of the 4 schottky diodes.
A half bridge is two diodes in a 3 terminal package (usually cathodes
tied together). If you could buy similar half bridges, one with
cathodes tied together, and one with anodes tied together, you could
make a full bridge out of them, but the common anode types are rare.
Half bridges are used most often with center tapped secondary
windings, where the two diodes take turns conducting current from
alternating halves of the winding on alternating half cycles. But if
you only have a single secondary winding (with no center tap) these
are not much use to you. The half bridge circuit is further down on