1N2071 diode speed

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I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?

Any ideas?

Thanks,

Michael
 
mrdarrett@gmail.com wrote:
I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?

Any ideas?
Click to expand...
Since the data sheet specifies no reverse recovery time, it
is going to be pretty slow, probably up to several
microseconds, depending on how high the forward current is
just before the voltage reverses.

You could set up a test and measure it under some particular
condition. Often, the reverse recovery time is measured
right after the diode has been conducting something like its
rated forward current, with the reverse current limited to
somewhere between double that current to perhaps half it and
a specified rate of change of current as it swings from
forward to reverse. And the time it takes for the reverse
current to fall to something like 1/4 or 1/10th of the peak
value is measured. It doesn't take a very complicated test
setup to do this.

See explanation of reverse recovery specs:
http://www.microsemi.com/micnotes/302.pdf
MIL-STD-750, Method 4031 for testing reverse recovery
starting at page 100 of:
http://snebulos.mit.edu/projects/reference/MIL-STD/MIL-STD-750D-Notice2.pdf

There was a time when the test setup was shown on every fast
recovery diode data sheet.

--
Regards,

John Popelish
 
mrdarrett@gmail.com wrote:

I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?
Click to expand...
Any diode designed for AC line power switching is probably good for
400Hz but don't bet on anything much above that.

What fun I've had with Chinese outfits fitting 1N4004s where I'd
specified UF4004s ! I imagine the remedy is not to use a part with the
number 4004 in it lest they try and get clever and specify a BYxx
something or other.

Graham
 
On Mon, 7 Jul 2008, mrdarrett@gmail.com wrote:

I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?
Click to expand...
What are you trying to do? You say "switch" which implies some sort
of logic or switching supply, but it's not completely obvious. What
you need a diode for helps to determine what will be suitable.

Since you're pulling things out of the junkbox, why not find a junk
computer, open up the power supply, and use the schottky power diodes
on the secondary for this project? They are readily available, and
since they are in switching supplies, they will be good at higher
frequencies.

Michael

Any ideas?

Thanks,

Michael
Click to expand...
 
On Mon, 7 Jul 2008 23:09:52 -0700 (PDT), mrdarrett@gmail.com wrote:

I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?

Any ideas?

Thanks,

Michael
Click to expand...
It's almost certainly a vanilla diffused-junction diode. Forward
recovery (turn-on time) is probably in the 100 ns ballpark, and
reverse recovery may extend into the microseconds, depending on the
situation. So it's probrbly fine to a few KHz, but it may make
recovery spikes and reverse recovery may increases losses (cause
heating) at higher frequencies and currents. Capacitance will be the
main problem at signal levels, but you can measure the cpacitance.

The higher voltage diffused diodes, like this one, tend to have
pin-diode-like behavior, so can be slow.

John
 
On Jul 7, 11:40 pm, John Popelish <jpopel...@rica.net> wrote:
mrdarr...@gmail.com wrote:
I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?

Any ideas?

Since the data sheet specifies no reverse recovery time, it
is going to be pretty slow, probably up to several
microseconds, depending on how high the forward current is
just before the voltage reverses.

You could set up a test and measure it under some particular
condition. Often, the reverse recovery time is measured
right after the diode has been conducting something like its
rated forward current, with the reverse current limited to
somewhere between double that current to perhaps half it and
a specified rate of change of current as it swings from
forward to reverse. And the time it takes for the reverse
current to fall to something like 1/4 or 1/10th of the peak
value is measured. It doesn't take a very complicated test
setup to do this.

See explanation of reverse recovery specs:http://www.microsemi.com/micnotes/302.pdf
MIL-STD-750, Method 4031 for testing reverse recovery
starting at page 100 of:http://snebulos.mit.edu/projects/reference/MIL-STD/MIL-STD-750D-Notic...

There was a time when the test setup was shown on every fast
recovery diode data sheet.

--
Regards,

John Popelish
Click to expand...

Ok, thanks!

Michael
 
On Jul 8, 8:25 am, Michael Black <et...@ncf.ca> wrote:
On Mon, 7 Jul 2008, mrdarr...@gmail.com wrote:
I found four 1N2071 diodes in my junk pile. Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.

I looked up the datasheet for the 1N2071. It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for
how quickly the diode can operate.

http://www.alldatasheet.com/datasheet-pdf/pdf/102157/IRF/1N2071.html

Can the diode successfully operate at up to 10 kHz? I have a sinking
feeling the answer is "no".

So, how quickly CAN the diodes reliably switch? 100 Hz? 400 Hz?

What are you trying to do? You say "switch" which implies some sort
of logic or switching supply, but it's not completely obvious. What
you need a diode for helps to determine what will be suitable.

Since you're pulling things out of the junkbox, why not find a junk
computer, open up the power supply, and use the schottky power diodes
on the secondary for this project? They are readily available, and
since they are in switching supplies, they will be good at higher
frequencies.

Michael

Any ideas?

Thanks,

Michael
Click to expand...

That's a good idea, thanks.

What I'm doing: I'm going to try and build my own mini switchmode
power supply, using pulses from a 555 in the kHz range to excite a
self-wound, center-tapped toroidal transformer, to convert 12V pulses
to +/- 24V, which must be recitified, of course.

Low power testing first, of course. ;-)

Ian: thanks for the low voltage warning, I'll look up the specs on
the high-frequency diodes when I find them

Another Michael
 
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