As a PhD I was excited when I found this forum something like this would
have been helpful when we switched from cats whiskers to valves, yes I was
around then.

I would like to build an ESR with a range selector switch, but for the
reasons that I joined this forum I am not able to follow all the discussions
and arguments associated with the build and use of an ESR which on the face
of it is a fairly simple circuit.
I am suffering from information overload. It is pleasing that so many will
take time to constructively discus the finer points of electronics but I do
have problems understanding some of what is said.

My 64$ question, is there a site similar to
http://ludens.cl/Electronic/esr/esr.html  that will give me Full details of
what to build.

Or could someone summarise the Ludens circuit and suggest how it can be
adapted to cover the points already discussed here and including a range
selector switch.

I have recently brought back to life a PC motherboard based on the fact that
the electrolytic caps had expanded, I changed them and have a motherboard
that is not yet going to landfill. I wonder how many items I could have
saved if I had had an ESR.

I like the forum but do find I spend time reading it when I should be
decorating etc etc.

Arthur

> -----Original Message-----
> From: Electronics_101@yahoogroups.com
> [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> Sent: quarta-feira, 31 de Agosto de 2011 23:51
> To: Electronics_101@yahoogroups.com
> Subject: [Electronics_101] Re: VLA517-01R datasheet
>
>
> Hello Nuno,
>     that is the data sheet I was referring to.  If you can
> figure out how to use to OCP time adj and alarm pins (4 & 5)
> from that data sheet you are cleverer than I.
>     Strange for an IgBT driver, there is not one diagram
> showing a connection to an IGBT.
>      That is what makes me think it must be truncated.

As far as I can see, that datasheet is all there. The specific info your
looking for is not included for some reason only they know...
(and makes this a very poor datasheet)

My guess is as good as yours on this.

Time adj pin is a trimmer to GND? Or the wiper of a pot from GND to VCC?
Capacitor somewhere in here?

Alarm pin is an output. Not much of a worry, you can measure it during
tests.


I would choose another Igbt module! One with a decent datasheet.

> M.
>
>
> --- In Electronics_101@yahoogroups.com, "Nuno T." <nuno-t@...> wrote:
> >
> > Sorry, the link got mixed up with another page, its this one:
> >
> > "http://www.farnell.com/datasheets/93237.pdf"
> >
> > And all the pins ARE there
> >
> > Nuno T
> >
> > > -----Original Message-----
> > > From: Electronics_101@yahoogroups.com
> > > [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> > > Sent: quarta-feira, 31 de Agosto de 2011 19:38
> > > To: Electronics_101@yahoogroups.com
> > > Subject: [Electronics_101] Re: VLA517-01R datasheet
> > >
> > > Hello NT,
> > >     nope, I dont see no link on that page.
> > >     There is a truncated datasheet available on Farnell,
> it doesnt
> > > even describe all the pins of the device.
> > > M.
> > >
> > >
> > >
> > >
> > > --- In Electronics_101@yahoogroups.com, "Nuno T." <nuno-t@> wrote:
> > > >
> > > >
> > > > "http://export.farnell.com/_/dp/1689601"
> > > >
> > > > There's a link to the datasheet on that page
> > > >
> > > > NT
> > > >
> > > > > -----Original Message-----
> > > > > From: Electronics_101@yahoogroups.com
> > > > > [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> > > > > Sent: terça-feira, 30 de Agosto de 2011 23:17
> > > > > To: Electronics_101@yahoogroups.com
> > > > > Subject: [Electronics_101] VLA517-01R datasheet
> > > > >
> > > > > Hello,
> > > > >      has anyone got a link to a detailed datasheet or
> > > > > application notes for Fuji's VLA517-01R IgBT gate
> driver.  I can
> > > > > only find a truncated datasheet.
> > > > > Thanks,
> > > > > M.

> My 64$ question, is there a site similar to

> http://ludens.cl/Electronic/esr/esr.html  that will give me Full details of

> what to build.


I think you mean this link ("electron" not "electronic")

http://ludens.cl/Electron/esr/esr.html


Jong












[Non-text portions of this message have been removed]

Arthur,


> My 64$ question, is there a site similar to
> http://ludens.cl/Electronic/esr/esr.html that will give me Full details of
> what to build.

Why not use that site?  :-)


The actual details of the circuit is VERY similar to what we have been talking
about.  Just about any circuit can be broken down into many little stages & some
glue "logic" to make each stage work.  In that circuit, you can break down the
stages as follow:

(1) power supply stage - (U2 - 78L05)
(2) 50khz square wave generator (U1A - TL062)
(3) DC blocking capacitor (C2)
(4) 5v to 200mV stepdown (T1)
(5) test probes
(6) DC block capacitor (C3)
(7) amplifier (U1B)
(8) DC blocking capacitor (C6)
(9) Max V limiter (D1)
(10) AC to DC rectifier (D2)
(11) Voltage "accumilator" (C7)
(12) Calibration (R11)
(13) meter (M1)

** I call the capacitor C7 voltage accumilator because (with D2) it allow the
voltage to sort of "BUILD UP", so that the meter can read it.

If you remember the discussion so far, we talked about using a battery, so that
is equivalent to U2 (stage 1 above).  

Then we talked about square wave generator using either a 555 or
micro-controller. That is equivalent to U1A (stage 2)

We talked about 1K & 22 ohm resistor to lower the signal from 5v to below
200mv.  That is equivalent to C2 + T1 (stage 3 and 4)

We did NOT talk about the probe, that was assumed.

And the rest of the stages (6 through 13) was equivalent to using an o-scope.

====

If you break things down they are about the same circuit (made differently).  In
fact if you break it down, you can make this SAME EQUIVALENT circuit in many
different ways.


Jong

[Non-text portions of this message have been removed]

An interesting discovery.

I think there is nothing wrong with the probe. The resistance is
apparently 83 Megohms. My meter (faithful Fluke 87V) registered this
as infinite.

Luckily this meter has Siemens range, and (when I eventually though
to use it) it measured 12 nS. That is equivalent to 83 Mohms.

Quite an eye-opening discovery for me: a tool is only as useful as
the tool that is using it.

Thanks to all who help me get where I am now. I'd like to thank my
kindergarten teacher, my 1st grade teacher, my 2nd grade teacher...

Dave

Yes Nuno,
     very poor datasheet.
     That's why I searched here.  Surely someone knows where to find the data? 
It is a very popular and widely available driver.

M.


--- In Electronics_101@yahoogroups.com, "Nuno T." <nuno-t@...> wrote:
>
>
>
> > -----Original Message-----
> > From: Electronics_101@yahoogroups.com
> > [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> > Sent: quarta-feira, 31 de Agosto de 2011 23:51
> > To: Electronics_101@yahoogroups.com
> > Subject: [Electronics_101] Re: VLA517-01R datasheet
> >
> >
> > Hello Nuno,
> >     that is the data sheet I was referring to.  If you can
> > figure out how to use to OCP time adj and alarm pins (4 & 5)
> > from that data sheet you are cleverer than I.
> >     Strange for an IgBT driver, there is not one diagram
> > showing a connection to an IGBT.
> >      That is what makes me think it must be truncated.
>
> As far as I can see, that datasheet is all there. The specific info your
> looking for is not included for some reason only they know...
> (and makes this a very poor datasheet)
>
> My guess is as good as yours on this.
>
> Time adj pin is a trimmer to GND? Or the wiper of a pot from GND to VCC?
> Capacitor somewhere in here?
>
> Alarm pin is an output. Not much of a worry, you can measure it during
> tests.
>
>
> I would choose another Igbt module! One with a decent datasheet.
>
> > M.
> >
> >
> > --- In Electronics_101@yahoogroups.com, "Nuno T." <nuno-t@> wrote:
> > >
> > > Sorry, the link got mixed up with another page, its this one:
> > >
> > > "http://www.farnell.com/datasheets/93237.pdf"
> > >
> > > And all the pins ARE there
> > >
> > > Nuno T
> > >
> > > > -----Original Message-----
> > > > From: Electronics_101@yahoogroups.com
> > > > [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> > > > Sent: quarta-feira, 31 de Agosto de 2011 19:38
> > > > To: Electronics_101@yahoogroups.com
> > > > Subject: [Electronics_101] Re: VLA517-01R datasheet
> > > >
> > > > Hello NT,
> > > >     nope, I dont see no link on that page.
> > > >     There is a truncated datasheet available on Farnell,
> > it doesnt
> > > > even describe all the pins of the device.
> > > > M.
> > > >
> > > >
> > > >
> > > >
> > > > --- In Electronics_101@yahoogroups.com, "Nuno T." <nuno-t@> wrote:
> > > > >
> > > > >
> > > > > "http://export.farnell.com/_/dp/1689601"
> > > > >
> > > > > There's a link to the datasheet on that page
> > > > >
> > > > > NT
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Electronics_101@yahoogroups.com
> > > > > > [mailto:Electronics_101@yahoogroups.com] On Behalf Of Michael
> > > > > > Sent: terça-feira, 30 de Agosto de 2011 23:17
> > > > > > To: Electronics_101@yahoogroups.com
> > > > > > Subject: [Electronics_101] VLA517-01R datasheet
> > > > > >
> > > > > > Hello,
> > > > > >      has anyone got a link to a detailed datasheet or
> > > > > > application notes for Fuji's VLA517-01R IgBT gate
> > driver.  I can
> > > > > > only find a truncated datasheet.
> > > > > > Thanks,
> > > > > > M.
>

Sure. It is an AC ohmmeter. A low impedance source supplies AC to the capacitor,
and the circuit measures the current by measuring the voltage across a reference
resistor.

It uses a high frequency so that the reactance of the capacitor is very low,
less than an ohm ideally.

The voltage used is very low both so you aren't reverse-biasing the capacitor to
any significant degree, and so that you can test in-circuit as the low voltage
won't activate any diode junctions.

I can give you a longer, more detailed answer after work. As it is, my lunch is
just ending.

Steve Greenfield AE7HD

--- In Electronics_101@yahoogroups.com, "Arthur Nichols" <arthurn@...> wrote:
>
> As a PhD I was excited when I found this forum something like this would
> have been helpful when we switched from cats whiskers to valves, yes I was
> around then.
>
> I would like to build an ESR with a range selector switch, but for the
> reasons that I joined this forum I am not able to follow all the discussions
> and arguments associated with the build and use of an ESR which on the face
> of it is a fairly simple circuit.
> I am suffering from information overload. It is pleasing that so many will
> take time to constructively discus the finer points of electronics but I do
> have problems understanding some of what is said.
>
> My 64$ question, is there a site similar to
> http://ludens.cl/Electronic/esr/esr.html  that will give me Full details of
> what to build.
>
> Or could someone summarise the Ludens circuit and suggest how it can be
> adapted to cover the points already discussed here and including a range
> selector switch.
>
> I have recently brought back to life a PC motherboard based on the fact that
> the electrolytic caps had expanded, I changed them and have a motherboard
> that is not yet going to landfill. I wonder how many items I could have
> saved if I had had an ESR.
>
> I like the forum but do find I spend time reading it when I should be
> decorating etc etc.
>
> Arthur
>

I did not say that 100kHz won't work as well as 50kHz. I was pointing out that
higher is not automatically better.

In my "free time" I'm working on designing an ESR/Capacitance/Low Ohmmeter. I'm
now in the midst of a move, which is good because I'll have a nice 1 car garage
for my lab (bwah hah, haah haa!!) and a 2 car garage for the workshop. On the
down side, it will be months before both are ready.

Steve Greenfield AE7HD

--- In Electronics_101@yahoogroups.com, jong kung <jongkung01@...> wrote:
>
>
>
>
> > I visualize the possibility of a dual range ESR instrument.
>
> I see that too.    How great minds do think alike.  (I just like to think
that... I might be...)
>
> They seem to want to make these pre-assembled ESR meter as PhD  ("Push Here
Dummy") type (very little in the way of buttons, settings, switches).  Simple
but not so flexible or accurate (imo).
>
> I remember thinking many, many moons ago, a more "customizable" ESR test rig
with variable freq & variable resistor config - all using o-scope (I have it -
so use it).  Plug in the o-scope into the test signal generator (with proper V
divider, etc.) and just use the prob to touch various caps.
>
> ====
>
> Even SG thinks that higher freq (100 Khz vs 50 Khz) may not actually work
better.
>
>
> Jong
>
>
> [Non-text portions of this message have been removed]
>

> I'll
have a nice 1 car garage for my lab (bwah hah, haah haa!!)
> and a 2 car
garage for the workshop.

2 car garage workshop.... WOW !!

You've just restored my faith that EE isn't dying hobby / profession.

===

You wanna know what I have 1 my 1 car garage?  1 car.    :-)


Jong


[Non-text portions of this message have been removed]

Mark,
If you look in the FILES section of this Yahoo Group you will find various
designs for ESR meters. I believe the most common belief is to generate a 100kHz
AC signal.

Good luck!

Frank P.

--- In Electronics_101@yahoogroups.com, mark hubrich <meistro57@...> wrote:
>
> Great, finally get to use it for something constructive :) Can I use an
> Arduino to generate my 100Khz? I think I can use the Tone Library get that
> value with a few lines of code. I could get that to work quicker if you
> think it would work good enough.
>
> Mark
>
> On Sun, Aug 28, 2011 at 10:30 PM, jong kung <jongkung01@...> wrote:
>
> > **
> >
> >
> >
> >
> > > I have an old HeathKit Scope
> >
> > Great!
> >
> > That's good enough. First you build 100Khz (that's 100,000 hz) square wave
> > oscillator. You can do that easily using many methods (including the OLD 555
> > IC). If this is unknown to you let us know - and we can show you the
> > circuits online.
> >
> > That is the HARD PART !!
> >
> > ====
> >
> > Now take the output (pin3 of 555) and feed it to a voltage divider (two
> > resistor in series) so the signal is about 1 milli-volt (if I remember
> > correctly). The low voltage allows you to test the capacitor IN-CIRCUIT !
> > The exact value (of resistors in voltage divider) depends on the power
> > supply (output of) 555 (your square wave generator).
> >
> > Now feed the tiny 1 milli-volt to your capacitor and scope the signal (also
> > across the capacitor).
> >
> > To learn the difference between good and bag capacitor (on a scope screen),
> > basically TEST it on good capacitor (new) and then ADD series resistor (of
> > various values from 1 ohm to 10 ohms to 20 ohms) and see the wave form
> > change. Remember that a BAD capacitor LOOK LIKE an ideal capacitor + SERIES
> > resistor.
> >
> > Now you will know how to recognize what a BAD capacitor (with HIGH ESR)
> > looks like on a scope.
> >
> > ====
> >
> > Let us know if any / all part of this is confusing. It really is NOT all
> > that complicated (it just sound like it all in words).
> >
> > Jong
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>

Subtopic: Unexpected oscillations in LTspice simulation.

--- In Electronics_101@yahoogroups.com, "Kerim F" <ahumanbeing2000@...> wrote:
>
> James,
>
> Just in case you have installed LTspice on your PC, I uploaded the files for
TesterC_04 in "TesterC_04.zip".
>
> But in case...
>
> Kerim
>
*****************

Kerim,

Thank you for uploading the ciruit SPICE files.

I simulated TesterC_04 in LTspice IV.  I was studying it when I saw something
that surprised me.  Although initially it appeared to be functioning properly,
further investigation revealed that some of the node voltages in the circuit
showed oscillations.  According to my understanding of the theory of operation
of the circuit, there should not be any oscillations in the circuit.  There is,
of course, feedback designed into the circuit and feedback sometimes results in
unintended oscillation or lock-up. I tried modifying the circuit to prevent
oscillation by putting one or more filter capacitors (i. e., low pass filters)
in the part of the circuit that has feedback.  However, so far such
modifications of mine have not succeeded in eliminating all oscillations.  One
of the nodes at which I was especially surprised to see an oscillation was the
positive input to the op amp labeled U2.  That input is connected only to a DC
voltage source through a resistor.  It is hard for me to imagine how an
oscillation could occur at that node in the actual circuit.  I presently suspect
that the oscillations may be some sort of LTspice artifacts.  That is, false
oscillations caused by some sort of convergence problem in the LTspice
simulator.  Do you have any thoughts on this?

James DePauw

5mv/div for vertical input would be considered good. You must have good grounds
in order to get meaningful measurements at 5mv/div. That is with a 1x probe. 10x
probe would be 50mv/div.
Charles  AE5EW

--- In Electronics_101@yahoogroups.com, jong kung <jongkung01@...> wrote:
>
>
>
>
>
> > No because of the sensitivity of the measuring instrument.
>
> > The OP said he had a Heathkit oscilloscope. Say the
>
> > oscilloscope had a sensitivity of 5 mV/cm.
>
>
>
> Did he say that (I missed it then) - or is that a ball park for old scopes.
>
>
>
> =====
>
>
>
> > Next I estimate the signal source amplitude at the output
>
> > of the micro controllers is 3 volts peak to peak. For a 10 ohm ESR.the
>
> > output signal is approximately 20.6 mV peak to peak For a 1 ohm ESR
>
> > the output signal is approximately 3 mv peak to peak. For a 0.33 ohm
>
> > ESR the output signal is approximately 1 mV peak to peak. Hence the
>
> > output signal will be less than 1 mV peak to peak for a ESR less than
>
> > 0.33 ohms. I doubt if a meaningful measurement can be made with a
>
> > signal amplitude less than 1 mV peak to peak.
>
>
>
> Oh man... I have to go back and crack open my old text book on Freq &
capacitors.
>
>
>
> Now I'm absolutely no expert on ESR, so if this is really dumb.... 
>
>
>
> Isn't 3 ohms about good enough for ESR meter ?  Aren't we looking for
> higher ESR (because most likely the failed capacitors are
> electrolytics).  Translated in other words, below certain low ESR, the
> trace on the o-scope will be basically flat (good).
>
>
>
> =====
>
>
>
> > It is a good thing you asked why. Upon review I see I was to
>
> > pessimistic the first time around.
>
>
>
> OK,  I don't fully understand but I'll take some sugar when I can get it.
>
>
>
> :-)
>
>
>
> =====
>
>
>
> > To measure ESR less than 0.33 ohms one could reduce
>
> > the size of the 1K resistor to say 100 ohms.
>
>
>
> (a) is 0.33 ohm realistic value ?
>
> (b) swapping 1K down to 100 ohm would probably not work because...
>
>
>
> ... because that makes the voltage greater than diode forward V and the
> capacitor won't be isolated from the rest of the circuit (translation:
> the capacitors then has to be removed from the circuit).
>
>
>
> I think the better option is to change the working freq (the real benefit of
using a microcontroller over hardware IC).
>
>
>
>
>
> Jong
>
>
>
> [Non-text portions of this message have been removed]
>

You need a good multimeter in order to measure the resistance of an HV probe
which could be on the order of > 100Mohms. Check out 'conductance
(Siemens/nanoSiemens)' of your multimeter. That is normally the way to check it.
The HV probe is a voltage divider in series with the input resistance of the
typical 10Mohm of a typical DMM. My Sencore FET multimeter actually uses 15Mohm
input and has a unique HV probe designed to match that. Fluke and other
manufacturers would NOT encourage anyone to try repairs of their HV probes.
Charles  AE5EW

--- In Electronics_101@yahoogroups.com, DaveC <davec2468@...> wrote:
>
> Fluke 80K-6 HV probe quit working.
>
> Disassembly and test of the thin-film(?) resistor shows no continuity
> to the tip.
>
> <http://oi54.tinypic.com/2eq8aj7.jpg>
>
> (The input wire broke during disassembly.)
>
> What would you do to resurrect this probe? I've seen a lot of DIY HV
> probes online but there's no room in the body of this probe for a
> dozen or so HV resistors.
>
> Ideas?
>
> Thanks,
> Dave
>

James,





> I simulated TesterC_04 in LTspice IV. I was studying it when

> I saw something that surprised me. Although initially it

> appeared to be functioning properly, further investigation

> revealed that some of the node voltages in the circuit

> showed oscillations.



Can you point out which node ?  More than one (I found one) ?





Jong





[Non-text portions of this message have been removed]

--- In Electronics_101@yahoogroups.com, "jamesmdepauw" <jamesmdepauw@...> wrote:
>
>
>
> Subtopic: Unexpected oscillations in LTspice simulation.
>
> --- In Electronics_101@yahoogroups.com, "Kerim F" <ahumanbeing2000@> wrote:
> >
> > James,
> >
> > Just in case you have installed LTspice on your PC, I uploaded the files for
TesterC_04 in "TesterC_04.zip".
> >
> > But in case...
> >
> > Kerim
> >
> *****************
>
> Kerim,
>
> Thank you for uploading the ciruit SPICE files.
>
> I simulated TesterC_04 in LTspice IV.  I was studying it when I saw something
that surprised me.  Although initially it appeared to be functioning properly,
further investigation revealed that some of the node voltages in the circuit
showed oscillations.  According to my understanding of the theory of operation
of the circuit, there should not be any oscillations in the circuit.  There is,
of course, feedback designed into the circuit and feedback sometimes results in
unintended oscillation or lock-up. I tried modifying the circuit to prevent
oscillation by putting one or more filter capacitors (i. e., low pass filters)
in the part of the circuit that has feedback.  However, so far such
modifications of mine have not succeeded in eliminating all oscillations.  One
of the nodes at which I was especially surprised to see an oscillation was the
positive input to the op amp labeled U2.  That input is connected only to a DC
voltage source through a resistor.  It is hard for me to imagine how an
oscillation could occur at that node in the actual circuit.  I presently suspect
that the oscillations may be some sort of LTspice artifacts.  That is, false
oscillations caused by some sort of convergence problem in the LTspice
simulator.  Do you have any thoughts on this?
>
> James DePauw
>

James,

I run "TesterC_04.asc" for 1u, 10u, 100u and 1000uF but I couldn't notice any
oscillation. Would you please upload yours?

Lately, I had a request to build a programmable controller for 8 x 8 LED matrix
(each pixel 600mA/48V DC). But just before I started the consumer's design, I
drew a possible tester version "TesterC_05a" to speed-up its reading. So, I
uploaded it now, as it is.

Kerim

There were 2 interesting messages about Arduino posted in the sci.electronics
group today and may be of interest to many in the electronics 101 group.

The first one shows an experimental setup the writer built. notice the $6.00
power supply.

"One like I built.

<http://i52.tinypic.com/1iel2e.jpg>
<http://i55.tinypic.com/bjecut.jpg>

I'm sure I spent well under $200 (if labor is not included). I built two
of them, one with the chipKIT Max32 Arduino board from Microchip and one
with the Arduino Mega2560.

What's on there:
Hex keypad
Speaker
DC Motor
Stepper Motor (need drivers, too much current to drive directly from
microcontroller)
Breadboard
LCD

Still room for some more stuff it I need it. I think I'll add some mini
toggle switches as many projects I do need switches and it's a hassle to
have them hanging all over the place.

The power supply (bottom level) is the one that our favorite troll got
so upset about me posting about here,
<http://www.mpja.com/prodinfo.asp?number=17602+PS>, buy a lot so I get
my huge kickback from MPJA, and remember to buy power cords too! Data
sheet at <http://i55.tinypic.com/mcu1c0.jpg>. It doesn't have to be that
supply of course, I wanted a slim power supply to keep the height low,
and this one was cheap and high quality.

Besides the power at the binding posts, I ran a separate power cable
over to the power input of the Arduino board with +12V.
<http://www.allelectronics.com/make-a-store/item/CB-204/2-CABLE-W/2.1M...>
was convenient.

The two layers are 1/4" plastic (8" x 12") from Tap Plastics, though you
could also use wood I suppose. Drilling the plastic is a bit tricky
since it tends to melt if you drill too fast.

The biggest hassle was finding all the various standoffs, 2-56, 4-40,
and 6-32, standoffs, washers (conducting and and non-conducting, screws
and nuts). There's one really tight mounting hole on the Arduino boards
that requires trimming the a phenolic or other non-conducting washer
(use 2-56 hardware for mounting the Arduino).

The little DC motor needed M2.5 bolts, which amazingly our local surplus
store had some of. The breadboard is bolted on with 2-56 bolts into the
soft plastic screw holes, but they don't tell you the size to use anywhere.

I also bought this shield:
<http://www.nkcelectronics.com/megashield-kit.html>

Some other stuff I'd suggest:
-Precut wire for the breadboard as well
-Resistor, capacitor assortment
-Some LEDs
-Stepper motor driver chip

This all took me back to my college days where we were all walking
around with various "Digi-Designers, i.e.
<http://gridchoice.com/catalog/images/BFB%20051%20003.jpg>.

It is very convenient to not have various bits and pieces strewn around
a bench or desk."


The second one is a list of links to instructional material and some interesting
projects.  The last link in the list is a link to many free online electronic
resources.

"These links should get him going. One thing leads to another.... I put the <>
around the long URLs to stop Microsoft's talent for wrecking them.

http://www.arduino.cc/
(of course)

a nice basic tutorial, from the beginning:

http://www.ladyada.net/learn/arduino/

From the same site:

http://www.ladyada.net/learn/sensors/cds.html

http://www.earthshineelectronics.com/files/ASKManualRev5.pdf
(8.2 Mb)

http://www.sparkfun.com/tutorials

<http://www.lulu.com/items/volume_63/1108000/1108699/4/print/ARDUINO_N...>
(350 Kb)

<https://sites.google.com/site/mechatronicsguy/arduinocheatsheet/Ardui...>

<http://rexonavn.com/download/manual/instructables%20GO/aHR0cDovL2N5Ym...>
( a coffee machine...8Mb pdf)

<http://mckgyver.pbworks.com/w/page/2065414/Firewood_Processor_Governor>
(wood cutter governor + video)

<http://sites.google.com/site/martinnile/automaticgeneratorcontroller>
Engine controller--well done article)

<http://www.freebyte.com/electronics/>"

Howard

Good job, Howard.  Looks nice and functional.

James "Jim" M. Geidl, K6JMG
No trees were harmed in the sending of this message; however, a large number
of electrons were terribly inconvenienced.







> -----Original Message-----
> From: Electronics_101@yahoogroups.com
> [mailto:Electronics_101@yahoogroups.com] On Behalf Of howard.hansen
> Sent: Friday, September 02, 2011 8:47 PM
> To: Electronics_101@yahoogroups.com
> Subject: [Electronics_101] Arduino
>
> There were 2 interesting messages about Arduino posted in the
> sci.electronics group today and may be of interest to many in
> the electronics 101 group.
>
> The first one shows an experimental setup the writer built.
> notice the $6.00 power supply.
>
> "One like I built.
>
> <http://i52.tinypic.com/1iel2e.jpg>
> <http://i55.tinypic.com/bjecut.jpg>
>
> I'm sure I spent well under $200 (if labor is not included).
> I built two of them, one with the chipKIT Max32 Arduino board
> from Microchip and one with the Arduino Mega2560.
>
> What's on there:
> Hex keypad
> Speaker
> DC Motor
> Stepper Motor (need drivers, too much current to drive directly from
> microcontroller)
> Breadboard
> LCD
>
> Still room for some more stuff it I need it. I think I'll add
> some mini toggle switches as many projects I do need switches
> and it's a hassle to have them hanging all over the place.
>
> The power supply (bottom level) is the one that our favorite
> troll got so upset about me posting about here,
> <http://www.mpja.com/prodinfo.asp?number=17602+PS>, buy a lot
> so I get my huge kickback from MPJA, and remember to buy
> power cords too! Data sheet at
> <http://i55.tinypic.com/mcu1c0.jpg>. It doesn't have to be
> that supply of course, I wanted a slim power supply to keep
> the height low, and this one was cheap and high quality.
>
> Besides the power at the binding posts, I ran a separate
> power cable over to the power input of the Arduino board with +12V.
> <http://www.allelectronics.com/make-a-store/item/CB-204/2-CABL
> E-W/2.1M...>
> was convenient.
>
> The two layers are 1/4" plastic (8" x 12") from Tap Plastics,
> though you could also use wood I suppose. Drilling the
> plastic is a bit tricky since it tends to melt if you drill too fast.
>
> The biggest hassle was finding all the various standoffs,
> 2-56, 4-40, and 6-32, standoffs, washers (conducting and and
> non-conducting, screws and nuts). There's one really tight
> mounting hole on the Arduino boards that requires trimming
> the a phenolic or other non-conducting washer (use 2-56
> hardware for mounting the Arduino).
>
> The little DC motor needed M2.5 bolts, which amazingly our
> local surplus store had some of. The breadboard is bolted on
> with 2-56 bolts into the soft plastic screw holes, but they
> don't tell you the size to use anywhere.
>
> I also bought this shield:
> <http://www.nkcelectronics.com/megashield-kit.html>
>
> Some other stuff I'd suggest:
> -Precut wire for the breadboard as well
> -Resistor, capacitor assortment
> -Some LEDs
> -Stepper motor driver chip
>
> This all took me back to my college days where we were all
> walking around with various "Digi-Designers, i.e.
> <http://gridchoice.com/catalog/images/BFB%20051%20003.jpg>.
>
> It is very convenient to not have various bits and pieces
> strewn around a bench or desk."
>
>
> The second one is a list of links to instructional material
> and some interesting projects.  The last link in the list is
> a link to many free online electronic resources.
>
> "These links should get him going. One thing leads to
> another.... I put the <> around the long URLs to stop
> Microsoft's talent for wrecking them.
>
> http://www.arduino.cc/
> (of course)
>
> a nice basic tutorial, from the beginning:
>
> http://www.ladyada.net/learn/arduino/
>
> From the same site:
>
> http://www.ladyada.net/learn/sensors/cds.html
>
> http://www.earthshineelectronics.com/files/ASKManualRev5.pdf
> (8.2 Mb)
>
> http://www.sparkfun.com/tutorials
>
> <http://www.lulu.com/items/volume_63/1108000/1108699/4/print/A
> RDUINO_N...>
> (350 Kb)
>
> <https://sites.google.com/site/mechatronicsguy/arduinocheatshe
> et/Ardui...>
>
> <http://rexonavn.com/download/manual/instructables%20GO/aHR0cD
> ovL2N5Ym...>
> ( a coffee machine...8Mb pdf)
>
> <http://mckgyver.pbworks.com/w/page/2065414/Firewood_Processor
> _Governor>
> (wood cutter governor + video)
>
> <http://sites.google.com/site/martinnile/automaticgeneratorcontroller>
> Engine controller--well done article)
>
> <http://www.freebyte.com/electronics/>"
>
> Howard
>

Small 12vdc fan needs to run from 24vdc supply.

Simplest solution is measure current and insert a v. dropping resistor.

More elegant solution is to use a voltage regulator.

If I understand correctly both will consume (waste) about the same power.

For such a simple application, is there any reason to use other than
a resistor?

Thanks,
Dave

Potentially the resistor solution could damage the fan.
There are transistors inside that power the coils as needed, when the
transistors are both off the full 24V would be applied to the fan
electronics.

In practice this often works anyway, perhaps because the voltage
rating is good enough or maybe the transistors are never both off,
there might be a capacitor, or perhaps just because we get away with
doing stupid things most of the time. Depends on the fan  I suppose.

The regulator solution will also work better with changing load
conditions such as obstruction, worn bearings, etc...

ST

On Sat, Sep 3, 2011 at 9:05 PM, DaveC <davec2468@...> wrote:
> Small 12vdc fan needs to run from 24vdc supply.
>
> Simplest solution is measure current and insert a v. dropping resistor.
>
> More elegant solution is to use a voltage regulator.
>
> If I understand correctly both will consume (waste) about the same power.
>
> For such a simple application, is there any reason to use other than
> a resistor?
>
> Thanks,
> Dave
>
>
> ------------------------------------
>
> Please trim excess when replyingYahoo! Groups Links
>
>
>
>

I haven't tried it, but you should be able to connect 2 in series.  I can see
how it might not work, because most small fans today (BLDC) have electronics
inside that may not agree with that arrangement.


HTH,

Jeff

Happiness is - positive intake manifold pressure.


________________________________
From: DaveC <davec2468@...>
To: Electronics101 <Electronics_101@yahoogroups.com>
Sent: Saturday, September 3, 2011 2:05 PM
Subject: [Electronics_101] Resistor or regulator?


 
Small 12vdc fan needs to run from 24vdc supply.

Simplest solution is measure current and insert a v. dropping resistor.

More elegant solution is to use a voltage regulator.

If I understand correctly both will consume (waste) about the same power.

For such a simple application, is there any reason to use other than
a resistor?

Thanks,
Dave



[Non-text portions of this message have been removed]

I've tried it, it works but all kinds of funny things happen if you
load one or even stall one.
Again probably only works because they put in much safety margin.

ST

On Sun, Sep 4, 2011 at 1:04 AM, Jeffrey Engel <jengeltx@...> wrote:
> I haven't tried it, but you should be able to connect 2 in series.  I can see
how it might not work, because most small fans today (BLDC) have electronics
inside that may not agree with that arrangement.
>
>
> HTH,
>
> Jeff
>
> Happiness is - positive intake manifold pressure.
>
>
> ________________________________
> From: DaveC <davec2468@...>
> To: Electronics101 <Electronics_101@yahoogroups.com>
> Sent: Saturday, September 3, 2011 2:05 PM
> Subject: [Electronics_101] Resistor or regulator?
>
>
>
> Small 12vdc fan needs to run from 24vdc supply.
>
> Simplest solution is measure current and insert a v. dropping resistor.
>
> More elegant solution is to use a voltage regulator.
>
> If I understand correctly both will consume (waste) about the same power.
>
> For such a simple application, is there any reason to use other than
> a resistor?
>
> Thanks,
> Dave
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Please trim excess when replyingYahoo! Groups Links
>
>
>
>

DaveC <davec2468@...> writes:
> If I understand correctly both will consume (waste) about the same power.

A linear regulator will, a switching regulator won't.

You can buy pre-packaged switching regulators but they're more expensive
than a new fan.

Near the bottom of the following web page is table of sample ESR readings.
<http://www.capacitorlab.com/esr-meter/>

And near the bottom of the following web page is a table of typical ESR values
for capacitors.
<http://en.wikipedia.org/wiki/Equivalent_series_resistance>

Some observations pop out.  Knowing what a manufacturers specification for the
ESR for a capacitor is, is a big help in determining whether a capacitor is good
or bad.  A capacitor with a high ESR is not necessarily bad.

Conclusion an ESR meter can be a big help in finding bad capacitors but it is
not perfect.

Howard

Hi Howard!
You have cleared many doubts.
Regards,
SG

On Sun, Sep 4, 2011 at 9:36 AM, howard.hansen <howard.hansen@...>wrote:

> **
>
>
> Near the bottom of the following web page is table of sample ESR readings.
> <http://www.capacitorlab.com/esr-meter/>
>
> And near the bottom of the following web page is a table of typical ESR
> values for capacitors.
> <http://en.wikipedia.org/wiki/Equivalent_series_resistance>
>
> Some observations pop out. Knowing what a manufacturers specification for
> the ESR for a capacitor is, is a big help in determining whether a capacitor
> is good or bad. A capacitor with a high ESR is not necessarily bad.
>
> Conclusion an ESR meter can be a big help in finding bad capacitors but it
> is not perfect.
>
> Howard
>
>
>



--
One of those ... ...


[Non-text portions of this message have been removed]

Inserting a resistor for the 12V drop is one thing, but takes experimentation as
to what value. Other option is to use a resistor to drop the voltage and a 12V
zener (in parallel with the fan). This will ensure 12V across the fan. But the
resistor will still dissipate power. Both cases you are effectively doing a
linear regulation.

Better yet... put the 12V zener in series with the fan. 12V drop across the
zener, balance across the fan.

Derek Koonce
DDK Interactive Consulting Services


--- In Electronics_101@yahoogroups.com, DaveC <davec2468@...> wrote:
>
> Small 12vdc fan needs to run from 24vdc supply.
>
> Simplest solution is measure current and insert a v. dropping resistor.
>
> More elegant solution is to use a voltage regulator.
>
> If I understand correctly both will consume (waste) about the same power.
>
> For such a simple application, is there any reason to use other than
> a resistor?
>
> Thanks,
> Dave
>

>Better yet... put the 12V zener in series with the fan. 12V drop
>across the zener, balance across the fan.
>Derek Koonce

I like that ides. Simplicity!

Thanks Derek.

Dave

--- In Electronics_101@yahoogroups.com, DaveC <davec2468@...> wrote:
>
> >Better yet... put the 12V zener in series with the fan. 12V drop
> >across the zener, balance across the fan.
> >Derek Koonce
>
> I like that ides. Simplicity!
>
> Thanks Derek.
>
> Dave
>

It is indeed if the maximum fan current is less than the rated zener one :)

Kerim

How about a resistor in series (to get the main drop) with a cap in parallel
with the fan (to provide some cushion for max/min current events).  One
disadvantage - takes three terminals now, instead of two (supply+, supply-,
fan+.)

Donald.
--
*Plain Text* email -- it's an accessibility issue
()  no proprietary attachments; no html mail
/\  ascii ribbon campaign - <www.asciiribbon.org>

----- Original Message -----
> From: "Derek" <derek@...>
> To: "Electronics 101" <Electronics_101@yahoogroups.com>
> Sent: Sunday, September 4, 2011 1:19:12 AM
> Subject: [Electronics_101] Re: Resistor or regulator?
> Inserting a resistor for the 12V drop is one thing, but takes
> experimentation as to what value. Other option is to use a resistor to
> drop the voltage and a 12V zener (in parallel with the fan). This will
> ensure 12V across the fan. But the resistor will still dissipate
> power. Both cases you are effectively doing a linear regulation.
>
> Better yet... put the 12V zener in series with the fan. 12V drop
> across the zener, balance across the fan.
>
> Derek Koonce
> DDK Interactive Consulting Services
>
>
> --- In Electronics_101@yahoogroups.com, DaveC <davec2468@...> wrote:
> >
> > Small 12vdc fan needs to run from 24vdc supply.
> >
> > Simplest solution is measure current and insert a v. dropping
> > resistor.
> >
> > More elegant solution is to use a voltage regulator.
> >
> > If I understand correctly both will consume (waste) about the same
> > power.
> >
> > For such a simple application, is there any reason to use other than
> > a resistor?
> >
> > Thanks,
> > Dave
> >
>
>
>
>
> ------------------------------------
>
> Please trim excess when replyingYahoo! Groups Links
>
>
>

--- In Electronics_101@yahoogroups.com, "Kerim F" <ahumanbeing2000@...> wrote:
>
> --- In Electronics_101@yahoogroups.com, DaveC <davec2468@> wrote:
> >
> > >Better yet... put the 12V zener in series with the fan. 12V drop
> > >across the zener, balance across the fan.
> > >Derek Koonce
> >
> > I like that ides. Simplicity!
> >
> > Thanks Derek.
> >
> > Dave
> >
>
> It is indeed if the maximum fan current is less than the rated zener one :)
>

True. With a small 12V fan at 120mA, x 12V is 1.44W. So you should have at least
a 2W zener, I'd feel better with a 3W or 5W. Starting current is going to be
higher, too, although for a brushless fan it should be a lot less than the old
standard DC commutating motors.

Of course, with one transistor you can "boost" the zener. A TO-220 transistor
has the advantage of 1. much higher current rating and 2. easily mounted on a
heat sink.

I'll call the zener Z1 and the transistor Q1 to save myself typing.

Q1 Collector to 24V
Z1 Anode to 24V
Z1 Cathode to Q1 Base
Q1 Emitter to motor +
Motor - to ground

You could add a low value resistor in series with the zener if connecting it to
the base in this way makes you nervous. If the motor fails short, which doesn't
seem to be a common failure mode, I think you'll fry Q1 and/or Z1 anyway. Unless
you make the circuit more complex. But if you are going to go to that much
trouble, why not just use a 7812?

Steve Greenfield AE7HD

That will have to be a really monster capacitor to have a long enough RC time
constant. And if the fan gets jammed, or some other long-term (ie, a few 10s of
seconds) failure, it gets over-voltage anyway.

Your fan will have a really slow start, too.

You would have to really match the RC time constant closely with the time to
full speed for the fan. However, the time to full speed will be much longer with
the RC circuit, so it will be quite a cut-and-try job. Which will change if the
in- or outtake vents become partly blocked by dust. As will the motor current.

My verdict is that a motor is much to complex a load to get good regulation with
a resistive voltage drop.

Steve Greenfield AE7HD

--- In Electronics_101@yahoogroups.com, Donald H Locker <dhlocker@...> wrote:
>
> How about a resistor in series (to get the main drop) with a cap in parallel
with the fan (to provide some cushion for max/min current events).  One
disadvantage - takes three terminals now, instead of two (supply+, supply-,
fan+.)
>
> Donald.
> --
> *Plain Text* email -- it's an accessibility issue
> ()  no proprietary attachments; no html mail
> /\  ascii ribbon campaign - <www.asciiribbon.org>
>
> ----- Original Message -----
> > From: "Derek" <derek@...>
> > To: "Electronics 101" <Electronics_101@yahoogroups.com>
> > Sent: Sunday, September 4, 2011 1:19:12 AM
> > Subject: [Electronics_101] Re: Resistor or regulator?
> > Inserting a resistor for the 12V drop is one thing, but takes
> > experimentation as to what value. Other option is to use a resistor to
> > drop the voltage and a 12V zener (in parallel with the fan). This will
> > ensure 12V across the fan. But the resistor will still dissipate
> > power. Both cases you are effectively doing a linear regulation.
> >
> > Better yet... put the 12V zener in series with the fan. 12V drop
> > across the zener, balance across the fan.
> >
> > Derek Koonce
> > DDK Interactive Consulting Services
> >
> >
> > --- In Electronics_101@yahoogroups.com, DaveC <davec2468@> wrote:
> > >
> > > Small 12vdc fan needs to run from 24vdc supply.
> > >
> > > Simplest solution is measure current and insert a v. dropping
> > > resistor.
> > >
> > > More elegant solution is to use a voltage regulator.
> > >
> > > If I understand correctly both will consume (waste) about the same
> > > power.
> > >
> > > For such a simple application, is there any reason to use other than
> > > a resistor?
> > >
> > > Thanks,
> > > Dave
> > >
> >
> >
> >
> >
> > ------------------------------------
> >
> > Please trim excess when replyingYahoo! Groups Links
> >
> >
> >
>