Is there a "classic" diode?

M

Michael

Guest
Is there a "classic" diode? One that is designed to do only what diodes are
famous for - only allow current to flow in one direction? I'm guessing that
it's the 1N4001 - because that's the diode I see used the most. But I could
also be completely off. What do you think? Thanks!

Michael
 
Michael wrote:
Is there a "classic" diode? One that is designed to do only what diodes are
famous for - only allow current to flow in one direction? I'm guessing that
it's the 1N4001 - because that's the diode I see used the most. But I could
also be completely off. What do you think? Thanks!

Michael
Click to expand...
Make it a 1N4004 and you are pretty close.

--
John Popelish
 
John Popelish <jpopelish@rica.net> wrote in
news:3FEE8314.BB75A87F@rica.net:

Michael wrote:

Is there a "classic" diode? One that is designed to do only what
diodes are famous for - only allow current to flow in one direction?
I'm guessing that it's the 1N4001 - because that's the diode I see
used the most. But I could also be completely off. What do you think?
Thanks!

Michael

Make it a 1N4004 and you are pretty close.
Click to expand...
I looked up the datasheet for the 4004 - and then I realized that it was
the same datasheet as the 4001!
(http://www.fairchildsemi.com/ds/1N/1N4004.pdf) So essentially 1N4001-
1N4007 are the same diodes - just with increasing Peak Repetitive Reverse
Voltages (which is something I'm not even familiar with - though using
common sense I have a good idea) So is there any reason that one couldn't
be substituted for the other in a design as long as you weren't expecting
the diode to encounter large Peak Repetitive Reverse Voltages? Also - does
this kind of diode come in a package with 18awg leads? I can't stand thick
leads...

Michael
 
Is there a "classic" diode? One that is designed to do only what diodes are
famous for - only allow current to flow in one direction? I'm guessing that
it's the 1N4001 - because that's the diode I see used the most. But I could
also be completely off. What do you think? Thanks!

Michael
Click to expand...

The "desert island" question for diodes. Hmmn....

1N400X -- Obvious choice for a first power rectifier diode. Good for 1 amp,
PRV dependent on X (get 1N4007 if you only want to stock one, because its PRV
is 1000V, and you can always substitute a 1N4007 for any of the others.
Inexpensive due to popularity.

1N914B/1N4148 -- These diodes sub for each other, as well as 1N914 and 1N914A.
One of the problems with the 1N400X is that it has a large diifuse die area and
high junction capacitance, and as a result isn't very good at high speed
rectification (anything over about 1KHz). When voltage across the diode
switches, the junction capacitance has to charge up before it blocks current,
and this charge passes through the diode. The 1N4148 is made with a smaller,
much better defined P-N junction, and so has less junction capacitance, and
works well at higher speed. It doesn't have as high a voltage or current
rating (75V @ 150 mA), but is very useful to have. This diode is also called a
"switching diode" or "computer diode". Again, inexpensive due to large volume.

The above would be the first two I'd get a hundred of just to have around in
the parts bin. After that, it kind of depends on where you want to go. The
above diodes are standard silicon. You have germanium and schottky diodes too,
as well as a wide range of currents/speeds/leakage current requirements.
That's why there are so many different kinds.

Good luck.
Chris
 
Michael wrote:
I looked up the datasheet for the 4004 - and then I realized that it was
the same datasheet as the 4001!
(http://www.fairchildsemi.com/ds/1N/1N4004.pdf) So essentially 1N4001-
1N4007 are the same diodes - just with increasing Peak Repetitive Reverse
Voltages (which is something I'm not even familiar with - though using
common sense I have a good idea) So is there any reason that one couldn't
be substituted for the other in a design as long as you weren't expecting
the diode to encounter large Peak Repetitive Reverse Voltages? Also - does
this kind of diode come in a package with 18awg leads? I can't stand thick
leads...

Michael
Click to expand...
The "Thick leads" are there to conduct heat away from the diode so it
doesn't overheat and fail. Buy a small pair of needle nose pliers to
shape the leads the way you want them.
--
Merry Christmas!

Take care, and God bless.
Michael A. Terrell
Central Florida
 
Michael wrote:
Is there a "classic" diode? One that is designed to do only what diodes are
famous for - only allow current to flow in one direction? I'm guessing that
it's the 1N4001 - because that's the diode I see used the most. But I could
also be completely off. What do you think? Thanks!

Michael
---------------------
Click to expand...
If you mean sort of like the 2N2222A/2N2907 and 2N3904/2N3906 are for
transistors, then yes. The "classic" small signal logic diode is the
1N914/1N4148, and the classic power diode is the 1N400x family, where
the x signifies ranges of breakdown PIV.

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
 
Michael wrote:
John Popelish <jpopelish@rica.net> wrote in
news:3FEE8314.BB75A87F@rica.net:

Michael wrote:

Is there a "classic" diode? One that is designed to do only what
diodes are famous for - only allow current to flow in one direction?
I'm guessing that it's the 1N4001 - because that's the diode I see
used the most. But I could also be completely off. What do you
think? Thanks!

Michael

Make it a 1N4004 and you are pretty close.

Also - does this kind of diode come in a package
with 18awg leads? I can't stand thick leads...

Michael
Click to expand...
The 1N4000S series come with 0.6mm leads (1N4000 are 0.8mm), mainly aimed at
auto-insert equipment, but they're the same price in small quantities. Rapid
do them in the UK
--
Correct address is cpemma at mexbro dot co dot uk
 
"CFoley1064" <cfoley1064@aol.com> wrote in message
news:20031228060448.26083.00001879@mb-m06.aol.com...

1N914B/1N4148 -- These diodes sub for each other, as well as 1N914 and
1N914A.
One of the problems with the 1N400X is that it has a large diifuse die
area and
high junction capacitance, and as a result isn't very good at high speed
rectification (anything over about 1KHz). When voltage across the diode
switches, the junction capacitance has to charge up before it blocks
current,
and this charge passes through the diode. The 1N4148 is made with a
smaller,
much better defined P-N junction, and so has less junction capacitance,
and
works well at higher speed. It doesn't have as high a voltage or current
rating (75V @ 150 mA), but is very useful to have. This diode is also
called a
"switching diode" or "computer diode". Again, inexpensive due to large
volume.
Click to expand...


Actually the junction capacitance isn't usually the reason why the 1N400X
series devices aren't appropriate for high frequency use. The 1N400X
devices are known as standard recovery rectifers. That is, their reverse
recovery time is quite long somewhere in the low microseconds range.
Reverse recovery currents are a different phenomena than the junction
capacitance displacement current, although they often both occur at about
the same time during a switching event and therefore are difficult to
separately distinguish.

If current is flowing in the forward direction through the diode at the
moment just before the diode becomes reverse biased, the diode will not
instantly start blocking the voltage/current. Instead a large transient may
occur momentarily until the diode can start blocking properly. The energy
contained in this transient is generally much larger than the energy that is
contained in the diode's junction capacitance, however the exact value is
not fixed, but depends on a number of factors such as die temperature, dI/dt
of the switching event, and the current that was flowing just prior to
polarity reversal. If forward current is not flowing through the diode
several microseconds prior to polarity reversal there will be no reverse
recovery transient.

The duration of this reverse recovery time can be reduced by deliberately
introducing impurity metals such as gold and platinum into the crystal which
introduces intermediate energy levels between the valence and conduction
bands. These extra energy levels serve as centers for recombination.
Diodes such as fast recovery, and ultra fast recovery use this type of
method to improve their switching performance.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top