1N4007 rectifier at 10kHz ?
J.-M. Noeding
I was told that 1N4007 type diode has poor performance at 10kHz.
Used it in a simple +12V to -10V inverter (NE556) with output load of
max 50mA, but could not measure/detect any problems with ofefficiency.
Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
and use RF signal diodes or schottky rectifier diodes instead?
---
J.M. Noeding, N-4623 Krsand
Eu VHFDX, wave...@onelist.com, GM4PLM 硬ave News',
UK-Vintage-Radio, VUSHF@SK7DO
Bob Wilson
>
>Hi
>I was told that 1N4007 type diode has poor performance at 10kHz.
>Used it in a simple +12V to -10V inverter (NE556) with output load of
>max 50mA, but could not measure/detect any problems with ofefficiency.
>Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
>and use RF signal diodes or schottky rectifier diodes instead?
First question: why the heck are you using a 1000 Volt rectifier at low
voltage at (relatively) higher frequency? The Trr time of a 1N4007 is the
very worst of the 1N400x family. But in any event, these devices are low
frequency rectifiers with absolutely abyssmal reverse and forward recovery
times. You might be able to get away with their use at 10HKz, but for the
same price, why not use a "fast" 1 Amp 1N4936 or 1N4938 rectifier? At least
it has a characterized Trr spec (around 200 nS).
Bob.
Mike Harrison
wrote:
>Hi
>I was told that 1N4007 type diode has poor performance at 10kHz.
>Used it in a simple +12V to -10V inverter (NE556) with output load of
>max 50mA, but could not measure/detect any problems with ofefficiency.
>Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
>and use RF signal diodes or schottky rectifier diodes instead?
>
>
>---
>J.M. Noeding, N-4623 Krsand
>Eu VHFDX, wave...@onelist.com, GM4PLM 硬ave News',
>UK-Vintage-Radio, VUSHF@SK7DO
Try the UF400x series - fast and cheap!
____ ____
_/ L_/ Mike Harrison / White Wing Logic / w...@netcomuk.co.uk _/ L_/
_/ W_/ Hardware & Software design / PCB Design / Consultancy _/ W_/
/_W_/ Industrial / Computer Peripherals / Hazardous Area /_W_/
Sam Goldwasser
> I was told that 1N4007 type diode has poor performance at 10kHz.
> Used it in a simple +12V to -10V inverter (NE556) with output load of
> max 50mA, but could not measure/detect any problems with ofefficiency.
> Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
> and use RF signal diodes or schottky rectifier diodes instead?
Supposedly - the reverse recovery time is not specified for the 1N400X diodes,
at least no place I could locate.
I have used them at 10 KHz without seeing any obvious problems but I prefer
to use fast recovery type diodes.
--- sam : Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Latest Sam stuff: http://www.repairfaq.org/sam/
Lasers: http://www.repairfaq.org/sam/lasersam.htm
http://www.misty.com/~don/lasersam.html
J.-M. Noeding
>
>First question: why the heck are you using a 1000 Volt rectifier at low
>voltage at (relatively) higher frequency? The Trr time of a 1N4007 is the
>very worst of the 1N400x family.
when you think it will replace the other. Interesting to note your
comment, seems to be the reason why 1N4007 works as a true PIN diode on
low RF frequencies, when the other in the 1N400x series do not.
> But in any event, these devices are low
>frequency rectifiers with absolutely abyssmal reverse and forward recovery
>times. You might be able to get away with their use at 10HKz, but for the
>same price, why not use a "fast" 1 Amp 1N4936 or 1N4938 rectifier?
again, it is a question of buying few different devices at a lower
price, since 1000 lot is cheaper than two 500 lots.
>At least it has a characterized Trr spec (around 200 nS).
>
anyhow, many thanks for your comments, but available data from Motorola
does not show differences between 1N4001 and 1N4007........
J.-M. Noeding
wrote:
>In article <35f05168...@news.online.no> LA...@online.no (J.-M. Noeding) writes:
>
>> I was told that 1N4007 type diode has poor performance at 10kHz.
>> Used it in a simple +12V to -10V inverter (NE556) with output load of
>> max 50mA, but could not measure/detect any problems with ofefficiency.
>> Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
>> and use RF signal diodes or schottky rectifier diodes instead?
>
>Supposedly - the reverse recovery time is not specified for the 1N400X diodes,
>at least no place I could locate.
>
>I have used them at 10 KHz without seeing any obvious problems but I prefer
>to use fast recovery type diodes.
>
MFJ uses the 1N400x type in a simple 10kHz inverter. I was surprised to
learn this, so in pure curiosity I tested the same circuit on 20kHz, but
did not experience any particular problems or losses. Many thanks for
your comments.
Don Klipstein
purpose rectifier diode on a "ringing choke" type inverter. This inverter
operated at several KHz (less than 10) and provided maybe 5 watts at 350
volts from 6 volts DC. Output was roughly 1.5 watts higher without higher
input current if I used a fast recovery rectifier.
I do not remember what type the general purpose rectifier was.
Your mileage may vary. If voltages are lower, losses due to slow
recovery will be less.
- Don Klipstein (d...@misty.com)
Tony Williams
<URL:mailto:LA...@online.no> wrote:
> On 5 Sep 98 05:18:58 GMT, rfwi...@intergate.bc.ca (Bob Wilson) wrote:
> >
> again, it is a question of buying few different devices at a lower
> price, since 1000 lot is cheaper than two 500 lots.
1N4000-series are commodity devices that may come from different
directions from different mfrs...... it is not unreasonable for
example to imagine that the '1N4000' devices you are using for
development may have come off some faster diode product-line.
Bearing in mind that the 1N4007 is not spec'd for this mode
of operation I would suggest trying samples from different
mfrs before committing myself on the dwgs.
--
Tony Williams.
Leland C. Scott
low current fast recovery diodes which should suite your design well.
http://mot-sps.com/sps/General/chips-nav.html
Leland C. Scott
Tony Williams wrote in message ...
jdr...@juno.com
I've used 1N4148s in switcher supplies and these will
handle up to 1 amp easy and 400F operation. About the size
and shape of a BB painted white with a band. The 1N4007
is too general for switchers. This is just an opinion.
Bill B.
LA...@online.no (J.-M. Noeding) wrote:
>Hi
>I was told that 1N4007 type diode has poor performance at 10kHz.
>Used it in a simple +12V to -10V inverter (NE556) with output load of
>max 50mA, but could not measure/detect any problems with ofefficiency.
>Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
>and use RF signal diodes or schottky rectifier diodes instead?
Sam Goldwasser
> I've used 1N4148s in switcher supplies and these will
> handle up to 1 amp easy and 400F operation. About the size
> and shape of a BB painted white with a band. The 1N4007
> is too general for switchers. This is just an opinion.
I hope these aren't in commercial production - the 1N4148 is only rated
100 or 200 mA continuous :-(.
--- sam : Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Latest Sam stuff: http://www.repairfaq.org/sam/
Lasers: http://www.repairfaq.org/sam/lasersam.htm
http://www.misty.com/~don/lasersam.html
Note: Temporary (I hope) problem with www.repairfaq.org, go to:
http://www.pacwest.net/byron13/sam/sammenu.htm
until remedied, sorry.
Spehro Pefhany
> I hope these aren't in commercial production - the 1N4148 is only rated
> 100 or 200 mA continuous :-(.
They are surprisingly rugged for parts that look a bit like the old glass
germanium diodes that would open up or short if you looked at them wrong.
I was a bit concerned about using them in a 20mA power supply application
(just due to start up surge into a 47uF voltage doubler) so I bench tested
them with the 200mA *rated* transformer short-circuited for 20 seconds or
so. They didn't fail! Obviously plenty of margin for the turn-on surge
(and we have shipped over 20,000 of these with no failures due to diodes).
(The main power supply in this unit uses a 1.5A rated bridge).
Since the cheapie transformer saturates very
close to the operating voltage, line surges are of no concern either.
Of course, it is essential to stay well within data sheet ratings under
all conditions if you want to ensure a reliable design regardless of any
changes that might take in subsituting manufacturers etc.
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany "The Journey is the reward"
sp...@interlog.com
Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Rgang6001
>
>Hi
>I was told that 1N4007 type diode has poor performance at 10kHz.
>Used it in a simple +12V to -10V inverter (NE556) with output load of
>max 50mA, but could not measure/detect any problems with ofefficiency.
>Is it a limit to avoid when using such 'cheap type AC rectifier' diodes
>and use RF signal diodes or schottky rectifier diodes instead?
>
Was the guy which told you this a purveyor of "expensive" rectifiers. Shottkey
will get you an incremental improvement due to lower Vf ~= 0.4 v
Chris
Jim_Thompson
*Years* ago I did some switching power supply loss studies. For
output voltages 5V and lower the largest loss is in the rectifier
forward drop followed by (a close second) reverse recovery time. Thus
the Schottky's are worth it. Harmonics up to the 9th order have
significant heating effects in the transformers, so use Litz wire.
(If replying by E-mail please observe method of anti-spam.)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(602)460-2350 | |
| Jim-T@analog_innovations.com Fax:(602)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
For proper E-mail replys SWAP "-" and "_".