Anybody tried one of these 5v transient suppressing regulators?

[BeanieBots]

Dippy, yes, you got it rolling and I'm sure others will now dive in!
Don't want to worry you, but did you know the Hilman Imp can now be viewed in the Beaulieu Motor Museum! Guess that dates both of us

Anyway, if you still had one and the battery was a little worse for wear, you could get a neon to light on the 12v bus
Did your tacho have a micro in it, or was it nice solidly designed descretes?
I agree about the fuse. Probably the most important part unless the circuit itself is important to car control, in which case I'd simply say DON'T DO IT.
600v AC caps should be fine. Not what was shown on your circuit though.

 

[Dippy]

Caps: You're right, I rushed it and only thought about X2 after drawing it and I couldn't be bovvered to update. I did put it on the link as it was an afterthought.

My imp was a 1971 which Mother gave to me in the eighties and the car lasted less time than my (non Micro) tachomter i.e. about a year whilst I was learning.
Actually, come to think of it , it was a Singer Chamois "Sport" with 875cc and 51bhp. Rusted like hell and the head gasket popped before my suppressor did.
Never tried a neon on the 12V but my radiomobile radio/cassette was perfectly happy.
Maybe you had a 1200V dynamo on yours?
I did put a 6V coil on it to get a bigger spark .... mmm... all I got was a bigger smell. Lesson learnt.


There you go Shafto, we've reminisced, so get on and build something. Don't bodge.
Don't have wires just soldered to board which can fracture or pull out.
Put it in a box with some strain-relief grommetty type things.
A properly manufactured in-line fuse should be a priority - and a few spare fuses.

All I will say (that makes a change eh?) is don't touch mega modern cars, many use electronic 'signalling' thru the loom and it is guaranteed that you will mess something up.

Remember, learn all your lessons with the car in neutral and handbrake (parking brake) full on. I'm not a gloom and doom merchant but just be careful and patient and don't rush and be careful with component selection and construction and assembly and installation and treble-check everything especially connections to loom.
There are so many things that can go wrong if you're not ultra-careful.
If it blows up send us a pic.

 

[MartinM57]

<aside>
My first car was a 1966 Hillman Imp - not in 1966 I hasten to add.

Ah, the joys of:
- making sure I had a very heavy toolbox in the boot (at the front) to make it turn in properly
- cutting 1.5 coils off the front springs to lower it
- replacing kingpins in the front steering seemingly every 3 months
- replacing head gaskets
- evacuating the car when the heater hose (in the sill) ruptured and filled the car with steam

It finally died when a cam bearing stud nut loosened, the cam flapped about, broke in two, stopped two sets of valves going up and down when the pistons were still going up and down...and there was a big bang and a split in the engine block
</aside>

 

[hippy]

"Who is responsible?"
You are. If you're not competant, don't do it.

If it blows up send us a pic.

That about sums it up.

What us 'doom and gloom merchants' ( and I am one ) worry about, is not so much the catastrophe waiting to happen, but people not taking responsibility for what they do and blaming everyone else but themselves when things go wrong.

In today's litigious and multi-million dollar lawsuit society there's a good chance that someone will blame whoever suggested an idea for not being clear about all the risks and therefore culpable or to blame in whatever happened. With International Arrest Warrants, deportation for trial with no pre-trial assessment of evidence these days, it's not impossible that one can find themselves on a plane to a foreign country to face a court hearing.

The problem for everyone giving advice these days is in how to frame it with a, "and don't blame me if it explodes", which actually holds up in court or is good enough to avoid getting dragged there. What should be blindingly obvious to all but the most stupid ( "don't cut your toe nails with a Black & Decker chainsaw", "don't stick lit fireworks up your backside" ) is fine until the most stupid decide that it wasn't clear to them, and people can become incredibly stupid when their lawyer tells them they're onto a chance of winning a few million. It wouldn't surprise me if there are people just looking for an opportunity to show how incredibly stupid they can be to gain a windfall.

Then there really are the intellectually challenged and inexperienced who would take a spin in a tumble driver or jump off a cliff if you told them to. We all have a duty of care towards those ( or more correctly government and society have decided we do these days ) and in the ether no one knows exactly who the target audience will eventually be..

That potential problems puts the onus on anyone giving advice to be very careful in what they say or risk the consequences. It means either saying nothing or explaining the risks explicitly, and then one ends up looking like an old fogey who's lost all idea of fun.

I blame the government and legal systems for creating the doom and gloom society coupled with people not taking responsibility for what they do. Trying to protect children ( and adults these days ) from all the ills of the world has also been counter-productive. In my day, one learned what not to do by going home in tears and then getting a good telling off or worse for being 'so stupid'. These days, protecting everyone from removing themselves from the gene pool means people don't have an understanding of what risk is and it often has to be spelled out.

As the McDonald's Hot Coffee / Hot Pop-Tarts cases is closely related to all this, I'll get in early and say the claimants were right, McD's were wrong. There's a difference between what most reasonable people would mean by Hot and what is Scalding which is what McD's served. The only reason we know others should be wary of McD's scalding foodstuffs is because we've fallen victim to it ourselves or know someone who has, but thankfully not injured enough to take it other than as a lesson learned.

 

[Dippy]

I agree with that, though I don't think Shafto will experience Extraordinary Rendition if his fuse blows.
BUT
It won't stop me doing things (legally) that are within my capability.

Having said that I don't touch major domestic electric jobs anymore as any nasty results will give the insurance company a get-out. I haven't been on the 3 day course or paid the fee.
This probably includes every insurable device these days.

Anyway, all this has been covered over and over dozens of times on the Forum. And it's getting to the point where people are going to be frightened off doing anything. And I know what the response to that sentence will be "..just trying to warn.. etc.". I would never suggest to a novice that a car project is undertaken. But anyone experienced and who is prepared to read-up and is good should have no problems. I worry slightly that this is shaftos first project judging by his/her comments?

Technical/Admin , please can we have a Grumpy Old Men section on the Forum?
(I'll join, I'm heading towards 40. But I really can't blame the Government for that.)

 

[BeanieBots]

I'm heading towards 40. But I really can't blame the Government for that.)

What/who do you think caused the post war baby boom then?

 

[Dippy]

Misspelt / Mis-spelt instructions produced by the London Rubber Company?

 

[hippy]

It won't stop me doing things (legally) that are within my capability.

What's legal is also being slowly but steadily restricted. Rules are being tightened so only those qualified can do things and the 'or competent and experienced person' escape clauses are fast disappearing. If the British Computer Society ever get their way and only qualified programmers are legally allowed to write code then that's probably a red flag that the world is doomed. Then there's the secondary legislation designed to punish anyone who does do work they shouldn't have.

Orwell simply got the date wrong.

 

[BeanieBots]

Good point Hippy.
Degree in electronics.
Qualified to teach somebody how to change a light bulb.
Not qualified to change one myself
Not allowed to wire a mains plug.
Am allowed to hook up 3-phase power plant.
but not if domestic
Am allowed to control 500kV generator

How does that all pan out then?

 

[Dippy]

When I worked for UKAEA there was a man who, armed with a degree in Electrical Engineering, asked how to wire up a battery+switch+light bulb.
Qualified shmalified.

Well, unions have wanted full demarcation for years. Now, they're getting it.

Having said that, I wouldn't want some idiot writing Space Shuttle code or being my Doctor.
I really don't think any of this doom/gloom will stop adventurous types, thank goodness.

I wouldn't want most people to build a suppressor for my car but I'd have a go without worry.


I went to my local Royal Mail distribution point the other day. A different bloke was on the main reception. I had forgotten my ID card. I said "Oh, just go and get Gary, he's known me for years". Bloke says "Sorry, Gary's having his nap at the moment. Come back tomorrow."
(Totally irrelevant I know, I just wanted get my Union slagging off my chest).

A new Sub_Forum for Grumpy Old Men is desparately required...!!

 

[Shafto]

Thanks again for more help...

The only equation I know off my heart is the equation for power, and ohm's law.. hah, when I made I first thread I may have made it out like I had a little more experience than I really do.. I didn't want everyone telling me I was over my head, which I may be, but I will find the surface, and it'll be great when I do... truth is I've never made anything to do with electronics more complicated than a switch, a resistor, and an LED... just hard to figure out everything I need for this before I actually start on it.. but I'm making progress... I'll post my final part order before I actually make it to see if I should be buying something else aswell, I was to get many common little building blocks of electronics that I might run into needing down the road.. as of now I don't really have anything.

so I'm thinking I'll take the easy way out.. and go with something like this:

http://pdf1.alldatasheet.com/datasheet-pdf/view/82303/COMCHIP/6KA24.html

There has to be some all in one IC automobile transient suppressor.. there has to be, they all must use them now.. this one right here looks like the money spot but unfortunately digikey doesn't have them in stock... I'm gonna request some samples from vishay, hopefully I get them. I did find some automobile varistors on digikey though, so I'll get one of those that looks suiting aswell.

That video that was posted up in the first thread, seen here: http://www.youtube.com/watch?v=K6sZg3iL5EY I've talked with that guy many times and he's using the same regulators I will be using for the LEDs since 2004 or something, with a 0.33 on the input and that's all... Almost everyone in the LED retrofitting scene uses these regs with no problems, I've never heard of an issue... though for the picaxe I can understand the need for power conditioning.

I will however take percaution, there will be 2 regs on each side for marker/brake, each will be fused individually, so if something were to occur to 1 reg only half of the LED array on either side would go out.. I will also rig up a bulb out sensor somehow... use one of those magnetic current sensing rings (what are those called?) into an analog picaxe input and if it fell bellow a certain level during braking a piezo could go off or something.. eventually I will use some green SMD LEDs up in the gauge cluster running sequentially like rear signals, I so will easily be able to see a problem there if there is one as it will use the same signal.

So what about the ceramic caps? do you guys buy the bypass specific ones? why are they $0.70 each? I'm very tempted to buy the general purpose ones.. especially since I imagine I'll be using quite a few.. I've heard one on every IC is a good idea.

 

[Dippy]

That first link is simply a TVS diode of a particular rating.
Yeah, buy it. Then what?
BB and I have given you tips how to build a simple suppressor - including how to incorporate a component like that one.

Of course you could have something more fancy.
But it sounds like you want a ready-made solution, so keep looking.
Maybe someone on this Forum knows of one. Maybe you'll be waiting six months for the answer you want.

Caps? BB and I have been on about this just a few postings ago.
Get the X2 or Y2 type. Whilt the X and Y defs are really safety aspects for mains operation it does mean that they are robust and can withstand higher voltages. Over-engineer it and 'err on the side of caution'.
"I'm very tempted to buy the general purpose ones..". Can if you want, but don't blame us if it goes pop!
For info on Capacitor type for Mains use:
http://www.evox-rifa.com/technote_pdf/rfi_fact.pdf


I'm afraid I have run out of suggestions.

 

[hippy]

when I made I first thread I may have made it out like I had a little more experience than I really do.. I didn't want everyone telling me I was over my head, which I may be, but I will find the surface, and it'll be great when I do

Unfortunately you chose a topic where most people would get the answer that it's over their heads

I've used the same trick in other places when discussing interfacing serial to a micro using just a current limiting resistor. Ask if it will survive +/-12V via an R and you can have a sensible discussion thread. Ask about interfacing serial via just an R and there's rarely a 'yes, that will work' answer, just endless repeats of "best use a MAX232", suggestions for other alternatives to a MAX232, comments about how it will not comply with true RS232C spec but no actual answer as to whether it'll catch fire or survive ;-)

The risk in overstating your abilities is that answers will get targeted at your perceived ability and may not be as useful as they could be.

 

[Shafto]

Bit of a typo there, I meant the first thread I made about sequential LED turns I may have pretended to know a little more.. now I do know a lot more than then.. hah.. haven't really gotten into how capacitance and inductance relate yet.

 

[Shafto]

About the caps, I don't see anything to do with X2 or Y2, are you talking about temp coefficient? because there's X7R which most of these ceramic caps are... here so some 10,000pF for a good price... general purpose X7R: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=BC1078CT-ND


But look at these 10,000pF "bypass caps" over 10X the price:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=709-1008-1-ND

 

[Dippy]

"not haven't really gotten into how capacitance and inductance relate yet."
- you really, with respect, need to look at Impedance theory. It ain't difficult.

You obviously didn't look at the link re Xwhatever Ywhatever.
It describes voltage ratings and how they fail. Sorry, can't help you.

 

[BeanieBots]

Ok, a little bit of Inductor (L) capacitor (C) theory.
The impedance of a capacitor is given by 1/(2*PI*f*C)
The impedance of an inductor 2*PI*f*L
Where PI=3.1415926, f=frequency in Hz, C=Farads & L=Henrys.
Those equations are fine when a sinusoidal wave form is applied but that is not the case with noise suppression. It gets horribly messy and involves imaginary numbers (root -1) but let's not get bogged down in all that here.
Just think of it terms of what is actually going on, without the need for full mathematical analysis. It is all still nothing more than ohms law except time is also involved. If you can do algebra and you know V=IR, then EVERYTHING else stems from that. All the other electronic equations are derived from that, with help of a little calculus!

A capacitor will impede a change in voltage by storing the current (as electrons on its plates) that is fed into it. The rate at which the voltage increases is proportional to the current and inversely proportional to the capacitance. dV/Dt = I/C

An inductor (choke) will impede a change in current by storing the energy as magnetism in its core. dI/dt=V/L

So, how does suppression work?
Let's consider a voltage spike.
A spike is a rapid rise in voltage. A rapid rise means high frequency.
If that was fed into a resistive load, it would lead to a rapid rise in current.

So, let's put an inductor in series between spike and load.
The inductor will try to impede the rise in current caused by the rise in voltage.
Let's add a capacitor to the load side of the inductor.
The capacitor will try to impede the rise in voltage by "soaking up" the current which in turn tries to increase the current through the inductor which as described earlier tries to impede current changes. Net result, the spike does not get through due to the inductor and capacitor working together to prevent any rapid current or voltage changes.
A bit like trying to pull a massive weight with an elastic band. The elastic is the capacitor and the inductor is the weight. (the maths is the same for the mechanical equivalent).

So, why don't we just use a big inductor and a big capacitor to do the job.
In simple theory, that would work. Unfortunatley, components are not perfect resistance, capacitance or inductance. ALL components have a certain amount of ALL three elements.
To make things worse for the poor old electronic engineer, the amount of each element that each component has, is also a function of other factors such as the rate of change of voltage and/or current. The inductor is a good example to explain. The inductance (number of Henrys) in an inductor depends on the number truns of wire wrapped around a core and the physical properties of the core. Soft iron is a common material to use but it is not possible to make very rapid magnetic changes in iron, so the inductance comes down as frequency goes up. Also, the coils of wire are close together. This is just like the plates of a capacitor. The capacitance is very small, so it is only a problem at very high frequencies.

Let's think about the capacitor. Many capacitors are made by rolling up layers of foil. Those layers are connected by wire. Rolled up? Wire? sounds just like an inductor!
Bottom line, at very high frequencies, an inductor can look like a capacitor and a capacitor can look like an inductor. The problem gets worse the higher the value. So, for VERY fast spikes, a large inductor and large capacitor is NOT what we want purely because the components are not perfect.

Anyway, that's enough for now. Hopefully you get the picture and can appreciate the difference between theory and real life practice.

 

[MartinM57]

<<You obviously didn't look at the link re Xwhatever Ywhatever.
It describes voltage ratings and how they fail. Sorry, can't help you.>>

I think you're being a little unfair....and I can see the confusion I think

The reference link is a bit of a (heck of a) heavyweight affair that categorises capacitors in to X and Y groupings etc

The OP is looking at a digikey stock listing, where it doesn't indicate whether a capacitor is X2, Y2, whatever.

The key for the OP is to read the ref link, understand the ratings and then go find real capacitors that have the same characteristics (where it will be found that the capacitors are made with dielectrics such as X7R and Y5V etc) Question: I thought the X7R, Y5V etc were mainly related to stability of capacitance vs. Temp - is it coincidence that the X and Ys are the same in the ref link and the common dielectrics?

What the OP really wants/needs is some specific direction on what suitable stock number items would be suitable....

 

[evanh]

I've seen over-current take out master breakers before individual ring breakers.

There is no master circuit breaker in a car last time I looked.

EDIT: Correction. Forgot about the inline fuse on the battery terminal.

I think you'll find the wiring to your regulator is too soft for taking out that big brute, you'll get a meltdown long before the master fuse goes. Unless we are talking about some insane subwoofer or something.

EDIT: EDIT: Just went and had a nosey under the bonnet and noted two fuses on my battery. One is 60 Amp, the other is 30 Amp. Not as big as I expected. Maybe you got a point...

That's weird, I've heard of and seen blown fuses from broken lighter/radio wires dangling where they shouldn't be and it's always just been the aux fuses that blow. Maybe the master ones are slow blows.


Evan

 

[Dippy]

evanh: I think you'll find hippy was referring to mains electric experiences. Ring main , MCBs etc. But opening the bonnet has given you a chance to check your oil and coolant maybe?

Martin, maybe I was a little abrupt.
It was just that by typing X2 or Y2 into Digi-Key search and then selecting 'poly film' under 'capacitors' it showed a huge selection , sadly some of those I looked at were non-stock. The variety is huge so I can't list everything. Example:
http://catalog.digikey.com/scripts/partsearch.dll?Detail?name=495-1644-ND
(keep in mind it sent me by default to UK section).

I did find this in Newark (if shafto is in USA?):-
http://www.newark.com/jsp/Passives/Capacitors/VISHAY+ROEDERSTEIN/F17724102030/displayProduct.jsp?sku=65C0137
I used the Advanced search and cunningly typed in "Suppression Capacitor"...

If Shfto is in UK places like Farnell and RS Components have loads.

 

[MartinM57]

...and
http://www.rapidonline.com/searchresults.aspx?style=0&kw=X2

 

[Dippy]

Blimey, they're cheap. Good old Rapid.

Good post BB.

 

[lbenson]

BB--thanks very much for the explanation. I've had trouble finding good (i.e., not overwhelming) explanations of inductors on the internet.

 

[Shafto]

Thanks very much for that explanation, and some specific parts.. all of the information that I was reading on capacitors on the internet was saying that ceramic were cheap and most common.. so I was looking under ceramic but astonished at the prices... now I see these polyester film caps are much better priced... I did read that doc about the x and y types, it can be hard to shop on digikey because they just have too much stuff it seems..

..by the way, I'm in Canada.

I'll make a little diagram of my proposed suppressor with all the parts I've chosen here pretty quick.. hopefully I think I may finally have it pretty much figured... I really do appreciate all this help.

 

[Shafto]

Well I didn't draw one up because it will be the same as the one posted by Dippy (thanks for that)

I will post up all the parts though, in the diargram you put "22u" I assume that's 22uF.. I'm still not familiar will all the acronyms and lingo. I couldn't get a 100pf x2 unless I wanted to buy 10, so hopefully a 1000pf will do, plus the varistor I chose has an internal capacitance of 22nF.

From reading this very helpful document:

http://www.epcos.com/inf/70/db/var_01/01930196.pdf

I get the impression all that is really needed is a varistor since it's built to deal specifically with load dump and other automobile specific transients.. at least I couldn't find any documentation saying that it should be used with other filters, or maybe they just assume that's obvious and I wouldn't know one way or the other.. either way it can't hurt things.. about the 15kv spikes, I found no info on that anywhere in all my googling.. mostly just the load dump.. which only occurs if your battery gets disconnected while the car is on... I'm not quite so sure the automobile enviroment is that bad, or all the guys I know running voltage regs with no filter cap even would have blown them up by now.. not to say that's right, because the potential is definitely there for some destructive AC and you need to deal with that, but I think the filter suggested by Dippy will be sufficient along with the best varistor I could find and the voltage reg designed for auto use... by the way, 100mA will be enough for the picaxe right? I heard that's the max it can draw.. which it won't though, as it will only be intermittently switching darlington arrays and putting out a PWM... I can't see that consuming a lot.

So here's my parts list.. I sure hope I have everything, it's taken me forever to compile this, I'm trying to get some of the most used basic building blocks of electronics here, so if you have any suggestions of other little handy things I might run into needing please suggest.

25x LM317TFS-ND IC REG ADJ 1.5A 3 TERM TO-220 $10.39 - current regs for high power LED (other project)
10x LM555CNFS-ND IC TIMER SINGLE 0-70DEG C 8-DIP $5.30 - for random stuff
5x CT94EW103-ND POT 10K OHM SQ CERMET TOP $7.35 - 18 turn input pot for picaxe
10x 3.6W-1-ND RES 3.6 OHM 1W 5% METAL OXIDE $1.21 - different resistors for different current from lm25
10x 1.6W-2-ND RES 1.6 OHM 2W 5% METAL OXIDE $1.46 - "
10x 1.8W-2-ND RES 1.8 OHM 2W 5% METAL OXIDE $1.46 - "
10x 1.2W-2-ND RES 1.2 OHM 2W 5% METAL OXIDE $1.46 - "
10x 22KH-ND RES 22K OHM 1/2W 5% CARBON FILM $0.56 - for picaxe serial interface
10x 47KH-ND RES 47K OHM 1/2W 5% CARBON FILM $0.56 - random
10x 4.7KH-ND RES 4.7K OHM 1/2W 5% CARBON FILM $0.56 - random
3x 568-1617-1-ND DIODE SCHOTTKY 30V 200MA DO34 $0.90 - for picaxe serial interface
5x ULN2803APG-ND IC DRIVER DARL 8CH 50V .5A 18DIP $3.90 - darlington arrays for switching LED arrays
10x 1.0KH-ND RES 1.0K OHM 1/2W 5% CARBON FILM $0.56 - random
15x 10KH-ND RES 10K OHM 1/2W 5% CARBON FILM $0.84 - random/picaxe interface
10x 497-1448-5-ND IC REGULATOR POS 9V TO-220 $5.61 - random
1x LM2931AT-5.0NS-ND IC REGULATOR LDO 5V TO220 $1.72 - picaxe power
200x 5.1QBK-ND RES 5.1 OHM 1/4W 5% CARBON FILM $4.12 - resistors for amber LEDs
200x 9.1QBK-ND RES 9.1 OHM 1/4W 5% CARBON FILM $4.12 - resistors for red/orange LEDs
1x 399-3839-1-ND CAPACITOR TANT 47UF 10V 20% SMD $1.50 - ESD matched cap for 5v reg hopefully I can solder this)
2x 3M5462-ND SOCKET IC OPEN FRAME 14POS .3" $0.32 - sockets for 14Ms I bought for other projects, I need a 28 pin socket too, but what spacing? 0.3" or 0.6" ? I couldn't find that in the manuals.
10x 399-3693-1-ND CAPACITOR TANT .33UF 35V 10% SMD $1.79 - input caps for 9volt regs I already have. 3.2x1.6mm smd, hopefully I can pull that off.
20x 1N4001-TPMSCT-ND RECTIFIER 1A 50V DO-41 $0.92 - random
15x ED2580-ND TERM BLOCK 5.08MM VERT 2POS PCB $3.99 - for the LED control board
10x ED2581-ND TERM BLOCK 5.08MM VERT 3POS PCB $4.00 - "
10x BC1078CT-ND CAP .010UF 50V CERAMIC X7R 10% $0.73 - bypass caps for ICs
10x BC1298CT-ND CAP .10UF 50V CERAMIC X7R 0805 $0.76 - "
10x 1N5402-E3/51GI-ND DIODE GP 3A 200V DO201AD $1.82 - random
4x 6A10DICT-ND RECTIFIER SILCON 1000V 6A R-6 $2.04 - blocking diodes for marker/brake input
1x M8274-ND CHOKE RF HASH 500UH 20% FERRITE $1.48 - choke for picaxe filter
3x 495-1451-ND VARISTOR 14V RMS 20MM RADIAL $1.77 - varistor for picaxe filter
1x BC1609-ND CAP FILM MKP .22UF 275VAC X2 20% $0.67 - X2 cap for picaxe filter (with 47ohm, how many watts for the resistor?)
10x 486-1172-ND FUSE-CLIP OG BRASS 5X20MM PCB $1.00 - fuse clips
2x 486-1234-ND FUSE 1A 250V 5X20 FAST GLASS $0.44 - fuse for picaxe
5x 180H-ND RES 180 OHM 1/2W 5% CARBON FILM $0.27 - for picaxe serial interface
1x BC1599-ND CAP FILM MKP .001UF 275VAC X2 $0.37 - second X2 cap for picaxe filter.

I think I have everything.. still need to add the 28pin socket and a 47ohm resistor for the filter of appropriate wattage.. also the choke I got isn't 3amp isn't only 2, I couldn't find anything in 3.. but how much power is gonna be going through there?

..oh and I bought a couple extra varistors, I plan on putting just a varistor before the 9 volt regs for load dump situations, should one arise.