2.7v voltage regulator for meters, cameras, etc.

ic-racer

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If you are going to try those out, please post your results, I'm interested to see how it works out.


For me, that looks almost too small to work with. This transistor-sized one might be easier to solder ( http://www.futureelectronics.com/en...tors/Pages/2502383-MCP1702-3302E-TO.aspx?IM=0 ) . Still small enough to fit in many locations. As long as the zinc/air cells are readily available at my local discount store, I have not done any hard-wired conversions on any of my gear. I have made physical adapters.

Another option I might consider is to solder the tiny TC-1015 to a board to make it easier to work with:
http://www.tirnaelectronics.co.uk/products/tirnadaptors.shtml
 
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E. von Hoegh

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Your first link has an 1100mv dropout. That means it needs at least 3.8v to provide a regulated 2.7v.
A magnifier and fine tipped soldering iron makes SMDs possible to solder.
The second link is far too large for many applications, and you still have to solder the SMD to it.
 
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E. von Hoegh

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So do I, as well as my FTn finder and Gossen LunaSix.
But it would be nice not to be dependent on the Z-A cells, these regulators would allow the use of pretty much anything that fits in the compartment.
Here's an adjustable regulator that might be suitable for things like Spotmatics which take a single cell, although I'd rather see one with a 100mv dropout.

What I like about the regulator is that the meter will work, getting a constant 2.7v, until the supply voltage falls too low for the regulator to work. Then it quits - not many of the single cell powered cameras had a test feature.
 
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Arvee

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My Spotties use 1.5v cells (387 and I think 392) with no problems; Spotmatics have a voltage regulating bridge circuit that work well with these batteries. I can also use the 312 zinc-air hearing aid batteries that are available at Costco for cheap (a 30 count pack).
 
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benjiboy

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The only camera I still have that takes PX625 1.3V mercury batteries is a Canon EF which fortunately has a built in voltage regulator and runs correctly on 1.5V silver oxide or alkaline cells.
 

Xmas

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Don't think you read the links a Shockety diode is simpler than a regulator.
SPOTTIES don't need any changes they are ok with alkalines
You are starting web rumors
 

Steve Smith

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Spotmatics certainly have a bridge circuit which is immune to voltage variations but it does not regulate the voltage.

E. von Hoegh said:
Here's an adjustable regulator that might be suitable for things like Spotmatics which take a single cell, although I'd rather see one with a 100mv dropout.
Click to expand...

Not necessary with a Spotmatic.

A bridge circuit will work with any cell which you can make fit and make contact.


Steve.
 

AgX

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Xmas said:
Don't think [E. von Hoegh] read the links, a [Schottky] diode is simpler than a regulator.
Click to expand...

Yes, more simpel.


But a diode

-) has to be chosen to the typical drain of the meter

-) has no cut-off feature
 

AgX

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Xmas, there is no Shockety diode. But there is a Shockley diode.

However, what you mean is a Schottky diode.
 

Xmas

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AgX said:
Xmas, there is no Shockety diode. But there is a Shockley diode.

However, what you mean is a Schottky diode.
Click to expand...

Correct

a diode is simpler to install it comes with long leads about one USD

and the silver cell has the cut off feature

And people offer off the shelf adapters

So hearing cell or diode and silver cell or replace tbe resistors of the meter

note many cameras don't need any rework eg a Pentax K1000 has a differential galvonometer.
 
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E. von Hoegh

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Xmas said:
Don't think you read the links a Shockety diode is simpler than a regulator.
SPOTTIES don't need any changes they are ok with alkalines
You are starting web rumors
Click to expand...

Rubbish. A diode with x value voltage drop is not a regulator. I made my point of the value of a regulator very clear. Spotmatics , at least mine, have a bridge circuit which is relatively insensitive to supply voltage.

And, by the bye, it's "Schottky". Not "Shockety". Getting the name right might lend you some credence...
 
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E. von Hoegh

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And I should make it clear that I'm getting tired of pi$$pots who know little or nothing, but throw rocks at every suggestion.
Xmas, you should try recalibrating a Nikkormat Ftn meter to use a silver cell. You have to exchange resistors, which are soldered in.

Next time I find a neat little thirty-nine cent gadget I'll keep it to myself, maybe.
 

BrianShaw

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Not intending to be a pi$$pot or ruffle feathers, but I never knew that there was a significant enough problem to warrant anything but a voltage-reducing diode solution. Not that another type of 39-cent solution that would address un-noticed voltage drop resulting in bad readings is a bad idea. I'm interested but wonder why Gossen didn't put one of those in their adapters in the first place.
 
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E. von Hoegh

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I think these ultra-low dropout regulators are fairly recent. The regulators literally cost thirty or forty cents, they allow the use of - as I said - almost anything you can get in the battery compartment - including lithium cells - and provide an elegant solution.

How much do those adapters cost??

As I indicated, I'm effing disgusted.

Edit - Gossen didn't put a regulator in their adaptor because if they did it would be 'on' all the time; the regulator I cited in the first post has IIRC a 2 microamp drain.
The regulator has to be put in the circuit after the switch.
 
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BrianShaw

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E. von Hoegh said:
How much do those adapters cost??
Click to expand...

A lot; I seem to remember $35 or so for the Gossen adapter. Others were/are less expensive.

When I bought mine I needed a quick and reliable solution that didn't involve DIY or fiddling with zinc-air cells.
 

Xmas

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I can salve SMD devices but it is well easy to cook them or even cook glass signal diodes.

The simple solution is an o ring from plumber supplies and a pack of hearing air batteries.

If you are practical you can solder in a diode.

If you are good with a soldering iron you can make an adapter from a used alkaline

Other wise eg email or PM Jon Goodman

But check first lots of cameras will work with a silver cell or alkaline and still be within 1/3 of a stop from bright to dark.

If you are lucky some one will have already fixed your camera for silver cells.

If you want you can fit a regulator but more complicated KISS is always best.

Real engineers cannot spell.
 

F4user

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No diode !!!
IF the metter need exactly 2.7 V the regulator is the solution
IF the metter is diferential ( Wheatstone bridge ) there is no need for voltage change as the galvanometer must be on "0" aka no curent flow in it.
http://en.wikipedia.org/wiki/Bridge_circuit

The voltage drop on a diode depend from curent flow so low curent -> low voltage almost unpredictible results.

The solution using voltage regulator is pro, others attempt .. fiddler.
 

BrianShaw

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Well apparently there have been some rather professional fiddlers in the past.
 

Xmas

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no the voltage drop through a diode is sensibly constant it is not like a passive resistor you describe.
You do need to select a reasonable diode.
Instructions are in links.
 

F4user

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xmas the difference between a diode and resistor is nonlinear characteristic versus linear in case of a resistor.
for any particular current the voltage across a resistor or a diode is always predictable.
you don't understand what i want to say.
more .. in case of constant current drain from batteries a simple resistor can adjust any desirable voltage drop.
for example gossen lunasix 3 is not bridge type so battrey voltage is important
so for large variation of a current " voltage regulation " using a diode is not appropriate

https://www.flickr.com/photos/5volt/8686556384/in/photostream/

from our father google :
"Mercury batteries using mercury(II) oxide cathode have a very flat discharge curve, holding constant 1.35 V (open circuit) voltage until about the last 5% of their lifetime, when their voltage drops rapidly. The voltage remains within 1% for several years at light load, and over a wide temperature range, making mercury batteries useful as a reference voltage in electronic instruments and in photographic light meters."
 
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E. von Hoegh

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My last post was deleted; "Reason Off topic and personal attacks".

The topic was that of this thread, voltage regulators. I mentioned no one by name, so where's the "personal attack"?
 
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