Battery question for flash unit

BAK61 · Oct 24, 2016

just received a flash unit that calls for A batteries. Honestly I have never heard of that size, but can't I just use AA cells ? Or are A cells readily available ? Thanks

benjiboy · Oct 24, 2016

Try AA cells and see if they fit..

skorpiius · Oct 24, 2016

A sized is 2.5 mm wider and .5 mm shorter than AA, so AA should work fine.

BAK61 · Oct 24, 2016

The AA's fit fine. The only thing is, an A cell is 1.2v and the AA is 1.5v. 3 batteries needed. I guess I'll wait for the bulbs to arrive, and try one.
Thanks

jacaquarie · Oct 24, 2016

Hope this helps a link to battery size charts, what you may be calling the battery could be more accurately described as the "cell".
The "A" cell or battery is 50mm long and 17mm in diameter

http://www.all-battery.com/sizechart.aspx

R23 (carbon‑zinc)
LR23 (alkaline) 17 × 50 More common as a NiCd or NiMH cell size than a primary size, popular in older laptop batteries and hobby battery packs.
Various fractional sizes are also available e.g. 2/3A and 4/5 A.

BAK61 · Oct 24, 2016

jacaquarie said:
Hope this helps a link to battery size charts, what you may be calling the battery could be more accurately described as the "cell".
The "A" cell or battery is 50mm long and 17mm in diameter

http://www.all-battery.com/sizechart.aspx

R23 (carbon‑zinc)
LR23 (alkaline) 17 × 50 More common as a NiCd or NiMH cell size than a primary size, popular in older laptop batteries and hobby battery packs.
Various fractional sizes are also available e.g. 2/3A and 4/5 A.

Thanks, I saw that. And another similar one. Like I said, a AA will fit, size wise. It's now a voltage question. There isn't much to a flash, electronically speaking. I'm not sure if there is a capacitor inside, and I'm not taking it apart to find out. There is no On/Off switch so I can't listen for that charging sound. I'm just going with the double A's and hoping for the best.
Unless I hear otherwise here.

shutterfinger · Oct 24, 2016

If it uses flash bulbs then you should be fine. Flash bulbs are current dependent, voltage is not important. 1.2*3=3.6. 1.5*3=4.5. Batteries of this type read .1 to .2 volts over stated nominal.

neilt3 · Oct 24, 2016

BAK61 said:
The AA's fit fine. The only thing is, an A cell is 1.2v and the AA is 1.5v. 3 batteries needed. I guess I'll wait for the bulbs to arrive, and try one.
Thanks

AA Alkaline batteries ( disposable ) are 1.5 volt .
Rechargeable AA's tend to have a voltage of 1.2 Volt , so if your concerned about the slightly higher voltage pop in some rechargeable ones .

BAK61 · Oct 24, 2016

Yep, it does use flash bulbs. And that is the answer I kind of was hoping for. I figured the over voltage would be fine, since it looks like the bulbs would fire right off the battery. I may end up getting more flashes with AAA than with A

shutterfinger · Oct 26, 2016

shutterfinger said:
Flash bulbs are current dependent, voltage is not important

I may be mistaken on that. The 1954 GE catalog and the 1964 Philips photo bulbs catalogs at http://www.donsbulbs.com/cgi-bin/r/t.pl via the Library link show common types to require 3V minimum.
The 1964 Philips catalog shows a range of 3V to 30V for their bulbs. The 1972 and 1985 Sylvania catalogs show a range of 3V to 45V for their flash bulbs.

The camera's shutter delay needs to be adjusted so that the shutter reaches full open no sooner than the time the bulb reaches 2/3 of peak light output. Some type M bulbs reach peak in 20 milliseconds while others reach it in 13 milliseconds and type F reach peak in 5 milliseconds. Useful light output is from 2/3 of peak to 1/3 after peak with a shutter speed of 1/30 second or slower.

AgX · Oct 26, 2016

BAK61 said:
Yep, it does use flash bulbs. And that is the answer I kind of was hoping for. I figured the over voltage would be fine, since it looks like the bulbs would fire right off the battery. I may end up getting more flashes with AAA than with A

In the past higher voltages were applied to overcome contact resistances. Designs seems to have been changed to lesser voltages due to the use of capacitators. Also the 22.5V battery seemed to have been the only small appropriate battery available. The 9V battery for instance was introduced later it seems.

DWThomas · Oct 26, 2016

The Honeywell Tilt-a-Mite used a 15 volt battery -- and a capacitor similar to the one that triggered this thread.

To my surprise, after a previous discussion about this flash I discovered the batteries could still be found. I would be very surprised if the cap was still good, but have no particular interest in shooting flashbulbs anyway.

Steve Smith · Oct 26, 2016

This flash probably charges a capacitor which is then discharged into the bulb to fire it.

Batteries have a high internal resistance which could cause problems getting a repeatable fire time. The low internal resistance of a capacitor ensures a quicker, higher current pulse which will fire the bulb more reliably.

Steve.

AgX · Oct 26, 2016

Steve Smith said:
This flash probably charges a capacitor which is then discharged into the bulb to fire it.

That is the way the second generation of electrical bulb flashes fire.

darkroommike · Oct 26, 2016

BAK61 said:
The AA's fit fine. The only thing is, an A cell is 1.2v and the AA is 1.5v. 3 batteries needed. I guess I'll wait for the bulbs to arrive, and try one.
Thanks

If the chemistry is the same, the voltage should be the same. If you really need 1.2 volts use a NiCad.

Leigh B · Oct 26, 2016

In this application, the original battery voltage would be a minimum for proper circuit function, not a maximum.

So a 1.5v battery would work fine, given that the original was rated 1.2 volts.

- Leigh

AgX · Oct 26, 2016

The OP has obviously has a flash that takes several type-A cells.
The lowest total voltage applied for a bulb flash I know of is 6V, and that is with a capacitator.

Leigh B · Oct 26, 2016

AgX said:
The lowest total voltage applied for a bulb flash I know of is 6V, and that is with a capacitator.

The capacitor is used as an energy storage device.
Flashes and similar applications require a high surge current (high amperage for a short time).

Small batteries are not good at supplying high surge currents. Capacitors are.
So the battery charges the capacitor, and the capacitor provides the energy to fire the flash.

- Leigh

DWThomas · Oct 26, 2016

The flash gun with my Argus C3 uses 2 'C' cells (3 volts) and I believe there were some husky looking units in the 1940s/early 1950s that used 3 'D' cells (4.5 volts) but C and D cells can supply several amperes of current. The 15 and 22.5 volt batteries like those seen above and used with a capacitor were probably gasping at a load of 50 mA.

shutterfinger · Oct 26, 2016

Early flash units called synchronizers for press style cameras used 2 or 3 D cells to fire flash bulbs. The 3 cell was used for flash and shutter solenoid operation. One brand is frequently cut up for a movie prop. A later version had case extensions available to hold 6 D cells total and BC , battery capacitor, remote flash units.
The smaller on camera units that used 15V or 22.5V batteries to charge a capacitor used that size battery for a higher number of flashes per battery or in other words to be more consumer friendly.

BAK61 · Oct 28, 2016

AgX said:
The OP has obviously has a flash that takes several type-A cells.
The lowest total voltage applied for a bulb flash I know of is 6V, and that is with a capacitator.

Takes 3 cells. It's a flash for a Viewmaster Camera.
Wouldn't a flash with a capacitor have an on /off switch, and the ability to fire it on its own ?

shutterfinger · Oct 28, 2016

BAK61 said:
Wouldn't a flash with a capacitor have an on /off switch, and the ability to fire it on its own ?

No information available on line about the flash. Viewmaster site recommends an electronic flash adapter and a hot shoe auto thrystor flash.
http://www.vmresource.com/camera/accessories.htm

Steve Smith · Oct 28, 2016

BAK61 said:
Wouldn't a flash with a capacitor have an on /off switch, and the ability to fire it on its own ?

No. The items are connected in series. Battery, bulb, capacitor, resistor then back to battery. With no bulb or a used bulb in the socket, no current flows. Plug in a bulb and current flows charging up the capacitor but limited by the resistor so there is not enough energy to fire the flash. The camera's flash contacts connect the other ends of the capacitor and bulb together so the bulb is connected directly to the capacitor when the shutter fires. This allows the capacitor to quickly discharge all of its stored energy into the bulb.

Steve.

AgX · Oct 28, 2016

That is why it is best not to keep a working bulb flash with the bulb installed (eg for the show), as a capacitator leak current may finally drain the battery.
Better in such case to take out the battery.

BAK61 · Oct 28, 2016

Frig it all, the bulbs fire with 3 AAs installed. Which is really all I care about. Thanks for all the help though.

Battery question for flash unit

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