Well, acording to a bunch of websites the electro 35's circuit will work fine w/ a voltage ranging from 4.9v up to 6v(or more, if I'm not mistaken).
I recall during the seventies, when mercury batteries were too expensive and not easy to find (specially in Brazil, the place where I was leaving during that time.) some brands had 5.6v but others "only" 5.4v, and they were sold as "original factory specs" replacements.
Since that time, I've heard about users having success finding alternative ways to power their Yashicas.
Today, most people use the smaller PX28x(6 volts) plus a commercial adapter. They claim there is no problem about light meter discrepancy, short battery life or "lack" of current flow.
But there are more alternatives: one cr123a plus a px625a. The author assures it works fine, despite the voltage provided is only 4.5v or so.
Using that idea as a start point, but not having those batteries in hand, I just made one experience using the only ones I had avaliable.
I used one lithium CR2(3 volts) from my Canon Rebel plus a half-ass 3 volts small lithium battery from my nikon EM. Since both batteries are much smaller than the original mercury or even the px28, I've surrounded both w/ carton strips plus a small spring at the upper end to assure good electrical contact. Everything worked fine.:-D
Using that setup, I've got a little less than 6 volts, mostly because my smaller lithium is really old.
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Makes sense people saying the Electro 35 has a great tolerance in the input voltage and will work fine no matter the voltage is 5.1v, 5.5v or even 6v.
It's electronic circuit is very primitive, having nothing more than 5 or six transistors (active components) and some resistors and capacitors (passive components). I believe the voltage is really not critical and voltage discrepancies will not alter the circuit performance or accuracy.
Now, talking about current-demmand(mA): The most "hungry" component is the magnet (but again, it does not need precise dc volt input).
Under normal use, the camera drains about 50-70 ma during operation. There is more details about this avaliable on the net. I've download some techinal stuff, but I'm not able to locate those files now, to give you more info about the electrical circuit.
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To make the Electro save yet more battery energy I had one crazy idea last week: Replace all 3 lamps by clear leds. This will save a considerable amount of battery power and even can be used in those cases when the lamp just burned. (it will need a little mod, adding a 100R, 1/8w resistor in series, but still a very easy task to acomplish). 🙂
If I'm not mistaken, the original mercury battery was capable of providing a current of about 500-600mA at best. Remember, size here does not matter. Mercury batteries are old technology (sixties) and modern lithium batteries are smaller but in current capacity they are strong enough to power Electro's circuit.
Just for the record: the CR2 has only half of CR123's capacity (in mA).
Best regards,
Zack (ZK)
