Lamps
The early Flash Lights used an Edison
type minature screw base lamp very much like the # 14. A problem
with this lamp is that the filament location is not controlled.
Part of the reason for that is there is no reference surface on the
base to support good filament location.
The single contact minature flange base used the flange surface as the refeence plane for locating the filament and so allows flashlight reflectors to be designed that have the filament at focus without any adjustments.
The 222 minature screw base Lamp has a built in lens and so does not need to be in a flanged base.
There seems to be a disconect between the battery makers and the lamp makers. The Leclanche type dry cells used have a nominal voltage when fresh of 1.5 volts so two in series would be 3.0 volts. The end of life voltage is taken as 0.9 or 1.0 so two in series would be 1.8 or 2.0 volts. The lamp voltages seem to be about half way. The 1915 patent 1163887 (see below) by Charles Burgess mentiones this and his lantern has a two position switch so that a resistor can be inserted for the first few hours of operation and then the direct connection made for the remainder of the battery life. It's my feeling he was correct, running the Pocket Flash Lights on a full 3.0 volts from a modern battery that's "stiff" will greatly shorten the life, if not just burn it out.\
This is a test stand I built to allow measuring the Voltage and Current of E10 based lamps. The Victor X solid lamp is in the stand for the photo. When it's on and you are looking at a side view like this there is not much light coming out, almost all the light is aimed in the narrow beam like for the 222.
The wood came from Michaels 85753336002 for 60¢. The expensive part was getting good wood bits. The brass hardware is from the No. 6 Dry Cell battery adapter and the wire is from the Hubbard spool which is 16 AWG solid copper, much larger than needed to light the bulb, but good for measuring the resistance of cold lamps.
This appears to be a single strand, not a coil so maybe a carbon filament rather than the more modern Tungsten type.
Q quick check of three os the flattened bulb type lamps showed they all had this type of "S" filament.
I'm fairly certain that all the other lamps have coiled Tungsten filaments.
The single contact minature flange base used the flange surface as the refeence plane for locating the filament and so allows flashlight reflectors to be designed that have the filament at focus without any adjustments.
The 222 minature screw base Lamp has a built in lens and so does not need to be in a flanged base.
There seems to be a disconect between the battery makers and the lamp makers. The Leclanche type dry cells used have a nominal voltage when fresh of 1.5 volts so two in series would be 3.0 volts. The end of life voltage is taken as 0.9 or 1.0 so two in series would be 1.8 or 2.0 volts. The lamp voltages seem to be about half way. The 1915 patent 1163887 (see below) by Charles Burgess mentiones this and his lantern has a two position switch so that a resistor can be inserted for the first few hours of operation and then the direct connection made for the remainder of the battery life. It's my feeling he was correct, running the Pocket Flash Lights on a full 3.0 volts from a modern battery that's "stiff" will greatly shorten the life, if not just burn it out.\
Lamp Test E10
This is a test stand I built to allow measuring the Voltage and Current of E10 based lamps. The Victor X solid lamp is in the stand for the photo. When it's on and you are looking at a side view like this there is not much light coming out, almost all the light is aimed in the narrow beam like for the 222.
The wood came from Michaels 85753336002 for 60¢. The expensive part was getting good wood bits. The brass hardware is from the No. 6 Dry Cell battery adapter and the wire is from the Hubbard spool which is 16 AWG solid copper, much larger than needed to light the bulb, but good for measuring the resistance of cold lamps.
Filaments
Eveready Mazda 1.5 Volt
This appears to be a single strand, not a coil so maybe a carbon filament rather than the more modern Tungsten type.Q quick check of three os the flattened bulb type lamps showed they all had this type of "S" filament.
I'm fairly certain that all the other lamps have coiled Tungsten filaments.
Table of Lamp Photos at 2X actual size.
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| # 14 T-3½ Bulb minature screw base 2.47 V @ 300 ma 0.5 MSCP |
25A like 222 prefocused TL-3 Bulb minature screw base |
# 27A PR4 T-3½ Bulb single contact minature flange 2.33 V @ 270 ma 0.4 MSCP 2.25 V @ 250 ma no CP rating not spherical |
PR6 bulb from MX-991 angle head army F.L. | Left Pocket Flash Light is the same as the
1047525 patent. Right is slightly newer, looks like patent. Notice left GE223 lamp has white bead on filament wires and has clear glass. Right EVEREADY MAZDA bulb has white reflector. black paing "2.5 V" As received both of these lamps have not wanted to come out. After soaking with Kroil a few days one was loose and the other came out with Scotch tape bent into "U" to grip lamp. | This is a prefocused lamp like the 222 only the lens is 10.8 mm dia instead of the 5.5 mm. Markings are: VICTOR X JAPAN 2.5V used in the Victor Pocket Flashlight | GE 1491 Dual Bayonet Prefocused 2.4 V 0.8 Amp 1.9 Watts Used in Dual No. 6 Dry Cell Navy Battle Lantern |
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| GE 407 Flasher Lamp has bi-metal strip 4.9 V 0.3 A 50 hrs 6 V lantern or baricade |
LED E10 base 2 to 12 V 1 Watt see: E10LED |
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GE 223 Lamp is rated for 5 hours at 2.25 Volts @ 0.25 Amps. After measuring the I-V curve from 0 to 215 ma and ploting in Excel shows the first few points coming up from zero to be off the straight line you get afterwards, so eliminating them and plotting from 125 to 215 ma gives this straight line:
I(ma) = 67.259*V + 104.9 with a fit of R2 = 0.9982
solving for 2.25 volts gives I(ma) = 256 ma, matching the published data pretty well.
solving for 3.0 volts gives I(ma) = 307 ma Would that burn out the bulb???
Testing a PR4 lamp rated 2.33 V @ 270 ma shows it's very close 2.4 V @ 271 ma. When the voltage gets to 3.7 the current starts to decrease with time, like the resistance is going up with time which might happen is the filament is starting to boil away.
Although given for currents close to the rated current these relationships give a feel for how incandescent lamps work.
Light ~ V^3.4 Power ~ V^1.6 Life ~ 1/V^16 Color ~ V^0.42
Because of the boiling temperature of tungsten the best possible efficiency is about 52 lumens/watt.
If a lamp is rated for 5 hours of life when operated at it's rated voltage it will burn out much earlier if operated at higher voltage. For example the GE 223 life might be described as:
Life = 2157200 / (V^16), so when V=2.25 Volts Life = 5 hr BUT at 3.0 Volts Life = 3 Minutes! One factor that may have allowed a longer bulb life in the old falsh lights is the internal resistance of the battery and flash light. An Ohm or two of resistance would bring the lamp voltage down to the spec for a battery with an open circuit voltage of 3.0 volts.
Edison 10 mm Miniature Screw Lamp Base (E10)
Based on measuring one I think the
thread is 14 TPI with a pitch diameter of 0.35 inches. Those
numbers are "nicer" than the metric equivalent 1.75mm pitch and 8.82 mm
pitch diameter. Let me know what
it really is. I'm guessing the 10 mm came from the fact
that these lamps were being made and sold in many countries, not just
the U.S.A. and metric was used in more locations.
Preserving Lamps
With the advent of LED based flashlights the filament type are going obsolete. Today most stores carry spare lamps I think in not too many years they will be harder to get and more expensive. Even today there are flashlight lamps that are fairly hard to come by. But being able to use the flashlight is a large part of it's appeal.The problem is that lamps are typically specified to operate at a voltage about half way between a fresh Carbon Zinc battery (1.5 Volts) and a dead one (1.0 Volts) or 1.25 volts per cell. You can see that in Table of Newer Lamps. But running a lamp above it's rated voltage. Note that a nominal lamp life is 15 hours at rated voltage.
Using modern Alkaline cells causes the lamps to burn brightly but not for very long. Using Ni-MH rechargeable cells drops the voltage from 3.0 V for fresh alkaline to about 2.8 V for fresh Ni-MH but they soon drop to 1.2 to 1.3 V per cell or 2.4 to 2.6 Volts which is very close to the specified operating point. So that's a rather simple way to preserve the lamp.
A better way is to use a current regulator to limit the current rather than regulate the voltage. With current regulation any resistance in the flashlight makes no difference to the lamp. With voltage regulation any resistance will make a big difference to the lamp. I like this approach a lot. It would allow adjusting the current so you could make the trade between brightness and lamp life.
Repairing Loose Bulbs
Quite a number of times the bulb has become unstuck to the base and is being held just by the two wires. If you apply any torque the wires will snap right were they enter the glass bulb and the lamp will be ruined. I can remember these seperated bulbs going back over 50 years.
The fix is to apply Loctite 290 (290 Data sheet, MSDS)to the crack between the bulb and base. It's designed to lock threads that are already mated. This is a penetrating liquid and is very thin. After cutting off the tip of the small tube the first time I used it way way more came out than I expected. So be very careful not to waste this expensive liquid.
The strength is best when the gap it's filling is smallest so I used a rubber jaw wood clamp to hold the bulb into the base and let it sit for more than 3 days (72 hour cure time). If repairing a lamp while it's still in a light be very careful that no thread locker gets on the base threads.
Available at Napa auto parts in 0.20 fluid ounce (6 ml) tube.
When a keychain UV LED is used to illuminate the bulb the Loctite 290 appears as a yellowish color where it's between the glass and base.
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| 290 Treated Lamp The glass to base area is clearly visible and an off yellow color. |
stock # 1491 The glass to base area is fuzzy with no yellow color. |
Lamp Patents
754251 Electric Lamp, Steinmetz (GE), Mar 1904, 362/329 ; 313/116 - home type by a key inventor762927 Composite Incandescent
774404 Base for Incandescent Lamps, Alfred Swan (GE), Nov 8 1904, 439/662 ; 439/663; 439/672; 439/675 -
The Ever Ready Osram lamps had this patent date marked on the base.
The Edison base was a cylinder that was all threads this invention makes the base more cup shaped and pours molten glass into the base that attaches to both the center contact and the base. It's mentioned on the Antique Christmas Light site about Eveready page 2.
825103 Method of Manufacturing Tipless Miniature Incandescent Search Lamps, O.A. Bohm, Jul 3 1906, 65/55- scarf pinsThe Edison base was a cylinder that was all threads this invention makes the base more cup shaped and pours molten glass into the base that attaches to both the center contact and the base. It's mentioned on the Antique Christmas Light site about Eveready page 2.
945823 APPARATUS FOR EXHAUSTING INCANDESCENT LAMPS
963872 Lamp-Filament, W.D. Coolidge (GE), July 12 1910, - Tungsten filaments replaced carbon filaments. One of the KEY lamp patents.
1712996 Incandescent Lamp, F. P. Hoffman (R.A. Schott), May 14 1929, 313/111 ; 220/2.1R; 313/110; 313/315; 362/296 -
bulb is mostly solid glass to both act as a lens and to be very strong (See Victor above)
1906188 Incandescent Lamp, Emamiel C. Smally, Apr 25 1933, 313/237 ; 174/50.51; 174/50.53; 174/50.55; 220/2.3R; 313/113; 313/312;
313/315; 313/318.04; 313/318.11; 313/324; 362/267; 362/296; 362/363
looks like an adapter to accept a small lamp and add a reflector and cover, but the small lamp does not need to have a glass bulb, just the base and filament
Reissued
looks like an adapter to accept a small lamp and add a reflector and cover, but the small lamp does not need to have a glass bulb, just the base and filament
Reissued
Osram Patents
These lamps have the word "OSRAM" inside the bulb and the word is what emits the light.
1675229 Electric
Incandescent Lamp, Franz Skaupy (GE), Jun 26, 1928, 312/305 ; 313/347; 313/45; 313/592; 313/8 - works like vacuum tube where the plate gets hot. "Osram" used in an example.1623761 ELECTRIC LAMP, Franz Skaupy (GE), Apr 5 1927, 313/9 ; 313/276; 313/316; 313/341 -
112 and 222 Lens Type TL-3 or GTL-3 Bulb
These are Edison miniature screw (E10) based lamps with a built in lens. Typically used in penlights. Since the lens to filament relationship is what's critical there is no need for a flange to locate the lamp with respect to the flashlight like in the PR- series of pre focused lamps. The support wires for the filament don't stop at the filament like on earlier lamps but instead continue upwards to a reference location. When the glass assembly with the filament is inserted into the bulb it stops when the top of the support wires hit the inside of the bulb at which point the glass is fused. This located the filament allowing for focus.1983362 Electric Incandescent Lamp, W.J. Geiger (GE), Dec 4 1934, [filed Apr 24 1934]- This is THE 222 method of locating filament at specific position for 112 and 222 lens type lamps.
2053164 Incandesent Lamp and Method of Manufacture, Marvin Pipkin (GE), Sep 1, 1936, 445/27 ; 220/2.1R; 313/110; 313/315; 313/317 - adds a solid glass lens to the bulb - 222?
2060658 Method of and Apparatus for Shaping Glass, Carl A. Brown (GE), Nov 10 1936, 65/109 ; 65/271; 65/276 - method of making glass lens on bulb, 222?
2416853 Incandescent Lamp, Emamiel C. Smally, Mar 4, 1947, 362/309 - adapter allows using a small lamp in a larger socket
References:
1906188 Incandescent Lamp
762927 Composite Incandescent Lamp-bulb and Reflector
1955601 Light Projector, Lamblin-Parent, Apr 1934, - glass cover for lamp with optical elements
1731714 Luminiar, WIXMAM A. DOBEY (Holopane Co)
1739679 Electric Lamps, WILLIAM L. LAIB, Dec 1929 - color filter as 2 pard shroud covers bulb
2004443 Lens, Kovac, Jun 1935 - a very complex shape of reflector behind lamp
1804049 Electric Lamp, Claus, May 1931 - incorporate reflectors, lens, multi filaments, etc.
2148314 Electric Lamp, D. K. WRIGHT (GE), - sealed beam that can be opened
2343754 Sealed type Tail, Stop and Directional Signal - complex lamp
2159736 Electric Lamp and Method of Making Same, Alfred T. Gaskill (GE), May 23, 1939 [filed May 22, 1934], 65/109 ; 65/DIG.1- Method of forming lens by melting tube This is for the 222 1906188 Incandescent Lamp
762927 Composite Incandescent Lamp-bulb and Reflector
1955601 Light Projector, Lamblin-Parent, Apr 1934, - glass cover for lamp with optical elements
1731714 Luminiar, WIXMAM A. DOBEY (Holopane Co)
1739679 Electric Lamps, WILLIAM L. LAIB, Dec 1929 - color filter as 2 pard shroud covers bulb
2004443 Lens, Kovac, Jun 1935 - a very complex shape of reflector behind lamp
1804049 Electric Lamp, Claus, May 1931 - incorporate reflectors, lens, multi filaments, etc.
2148314 Electric Lamp, D. K. WRIGHT (GE), - sealed beam that can be opened
2343754 Sealed type Tail, Stop and Directional Signal - complex lamp
2277633 Electric Lamp and Mounting, Joseph D. Ceader (GE), Mar 24 1942, 362/202 ; 362/341 - Prefocused Flashlight lamp. uses a small donut shape in the metal base next to the glass. Notice that a lamp like the #14 shown in the photo above must be inserted from the front of the reflector, but the flanged lamps have been designed to allow inserting from the back of the reflector.
2235515 Manfacture of Miniature Lamps, Walter E. Carpenter, (Westinghouse Electric), Mar 18 1941, 174/17.08 ; 174/50.58; 220/2.2; 313/315; 313/318.03; 313/318.08; 445/27; 65/46; 65/56; 65/57 - glass blowing and stept of making PR- type pre focused lamps
1915 Catalog listing of Lamps
| No. |
V |
Bulb | CP? |
| 1180 |
2.6 / 2.3 |
? |
|
| 1181 |
3.3 |
FE-3 3/4 | 0.25 |
| 1182 |
2.3 |
FE-3 3/4 |
0.27 |
| 1197 |
2.3 |
G-3½ | 0.27 |
| 1162 |
3.8 |
G-3½ | 0.30 |
| 1161 |
2.5 |
G-3½ | 0.30 |
| 1166 |
2.4 |
G-3½ | 0.60 |
| 1167 |
3.6 |
G-4½ | 0.60 |
| 1168 |
6.0 |
G-5 |
0.60 |
| 1163 |
6.2 |
G-4½ | ? |
| 1117 |
2.4 |
G-3½ | ? |
| 1135 |
6.3 |
T-3¼ | ? |
| 1149 |
2.5 |
T-3¼ |
? |
| 1109 |
5.0 |
G-4½ | ? |
| 1173 |
2.3 |
G-3 Frosted |
? |
| 1174 |
2.5 |
GL-3½ |
? |
| # Cells |
Model |
Base |
Bulb |
Volts |
Amps |
Power Watts |
Life hrs |
| 2 |
223 | E10 |
FE3-4/4 |
2.25 |
0.25 |
1/2 |
5 |
Table of Newer Lamps
5| # Cells |
Model |
Base |
Bulb |
Volts |
Amps |
Power Watts |
Life hrs |
| 1 |
112 |
E10 |
TL3 | 1.2 |
.22 |
1/4 |
5 |
2 |
14 |
G3-1/2 |
2.47 |
.3 |
3/4 |
15 |
|
| 222 |
TL3 |
2.25 |
.25 |
1/2 |
5 |
||
| PR-9 | P13.5s |
B3-1/2 |
2.7 |
.15 |
1.2 |
45 |
|
| PR-6 | B3-1/2 | 2.47 |
.3 |
3 1/2 |
30 |
||
| PR-2 |
B3-1/2 | 2.38 |
.5 |
1 |
15 |
||
3 |
13 |
E10 |
G3-1/2 | 3.7 |
.3 |
1 |
15 |
| PR-7 |
P13.5 |
B3-1/2 | 3.7 |
.3 |
1 |
30 |
|
| PR-3 |
B3-1/2 | 3.57 |
.5 |
1 3/4 |
15 |
||
| PR-30 |
B3-1/2 | 3.75 |
.86 |
3 1/4 |
40 |
||
| 4 |
27 |
E10 |
G4-1/2 |
4.9 |
.3 |
1 1/2 |
30 |
| PR-13 |
P13.5s | B3-1/2 | 4.75 |
.5 |
2 1/2 |
15 |
|
| 5 |
PR-12 |
P13.5s | B3-1/2 | 5.95 |
.5 |
3 |
15 |
| 6 |
PR-18 |
P13.5s | B3-1/2 | 7.2 |
.55 |
4 |
3 |
| 8 |
965 |
E10 | T4-1/2 | 9.84 |
.5 |
5 |
15 |
Integrating Sphere
Looking for information on design etc.1979952 Reflectometer, Benford (GE), Nov 6 1934, 356/448 ; 356/236; 356/446 - mentiones integrating sphere
2126410 Spectrophotometer, O. W. Pineo (Calco Chemical Co), Aug 9 1938, 250/204 ; 250/225; 250/228; 359/281; 40/548 - uses Magnesium Oxide coating inside sphere
2046958 Colorimeter,Harry B. Marvin (GE), Jul 7 1936, 356/319 ; 356/405 - measures spectral output of lamps and uses integrating sphere
2189270 Photometer, Orrln Western Pineo, Feb 6, 1940, 250/204 ; 250/225; 250/228 - uses Magnesium Oxide coating inside sphere
2342771 Photometric Apparatus, Voigt, Feb 29 1944, 356/364 ; 250/339.07; 250/339.09; 346/128; 346/33A; 346/33R; 356/236; 356/321; 356/323 - showing a number of setups
2263938 Light Sensitive Measuring Instrument, Douglas L. West (Howard Smith(Paper Mills Ltd), Nov 25 1941, 356/369 ; 250/208.6; 250/226; 250/228; 356/243.1; 356/416; 356/448 -
2326007 Sensitometer, J. G. CAPSTAFF (Eastman Kodak), Aug 3 1943, 356/433 ; 355/83; 356/443; 359/888
2601182 Photometric Apparatus, John E. Tyler (Interchemical Corp), Jun 1952,356/321 ; 250/205; 250/225; 250/226; 250/228; 250/229; 315/166; 315/257; 315/296; 356/325 -
From the box of a green full size Edison base 12V 5Watt lamp:
532760 Incandescent Lamp, Mark Branin (GE), Jan 22 1895, 174/50.58 ; 220/2.1R; 445/27; 65/59.28
537693 Process of Evacuating Incandescent Lamps, Arturo Malignani (Italy), Apr 16 1895, 445/20 ; 252/181.1; 252/181.2; 313/315; 313/548; 417/48
575668 Illuminant for Incandescent Lamps, A. De Lodyguine (Jan 19 1897, 428/663 ; 29/527.4; 420/429; 427/111; 427/117; 427/124; 427/252; 427/594; 428/670; 428/938; 445/48; 75/10.28
726293 Exhausting Lamps, John W. Howell (GE), Apr 28 1903, 445/20
729730 Incandescent Lamp, William. Buerows (GE), Jun 2 1903, 313/42 ; 313/40; 313/43
774404 Base for Incandescent Lamps, Alfred Swan (GE), Nov 8 1904 - see above
916659 Producing Metallic Incandescent Bodies for Electric Glow-Lamps, Fritz Blau (Germany), Mar 30 1909, 419/4
919381 Electric Glow Lamp, Hermann Remand (Germany), Apr 27 1909, 313/271 ; 313/277; 403/270
Batteries
By 1910, 11 years after flash lights were invented there were a number of batteries available from National Carbon Co. using the Columbia brand.A Brief History of the Standardization of Portable Cells and Batteries in the United States by
My seperate Battery Patents web page.
Cylindrical
| No. |
dia x ht |
No. of Cells |
Wt oz |
Volts |
| 1 |
1 3/8 x 7 1/8 |
3 |
11.5 |
4.5 |
| 20 |
1 3/8 x 9 1/2 |
3 |
15 |
4.5 |
| 30 |
1 3/8 x 11 7/8 |
5 |
18 |
7.5 |
| 110 |
1 x 4 3/4 |
2 or 3 |
8 |
3 or 4.5 |
| 590 |
1 3/8 x 4 3/4 |
2 |
3.5 |
3 |
| 591 |
1 x 3 7/8 |
2 |
3 |
3 |
| 1915 Catalog |
||||
| 935 "C batt" | 1 31/32 x 1 1/32 | 1 | ||
| 950 | 2 13/32 x 1 11/32 | 1 | ||
| 705 | 7 15/64 x 1 11/32 | 3 | ||
| 706 (~2xAA) | 4 1/31 x 19/32 | 2 |
||
| 710 |
2 31/32 x 3 9/32 | 5 ? | ||
| 790 | 4 13/16 x 1 11/32 | 2 | ||
| eBay |
||||
| BB21 Rayovac |
C 1 31/32> dia > 9/16 AA |
2? |
||
Prismatic
Dimensions exclude the metal tabs.| 1910 National Carbon Co. |
||||
| No. |
thk x w x ht |
No. of Cells |
Wt oz |
Volts |
| 032 |
2 5/8" x 1 3/8" x 3/4". | 2 |
3 |
|
| 502 |
fits patent dwg Pocket F.L. |
? |
? |
? |
| 592 |
13/16 x 1 5/8 x 2 1/2 |
2 |
3 |
3 |
| 593 |
1 1/16 x 2 1/16 x 3 1/2 |
2 |
7 |
3 |
| ECP |
1 1/4 x 3 1/8 x 4 1/16 |
3 |
12 |
4.5 |
| CP3 |
1 1/8 x 3 1/4 x 3 3/4 |
3 |
15 |
4.5 |
| EVP |
15/16 x 2 1/2 x 3 1/8 |
3 |
6 |
4.5 |
| OV3 |
7/8 x 2 1/8 x 2 9/16 |
3 |
6 |
4.5 |
| OV3 import |
7/8 x 2 3/8 x 2 9/16 |
3 |
6 |
4.5 |
| OVN |
7/8 x 2 3/8 x 2 9/16 |
3 |
5 |
4.5 |
| 1915 Catalog |
||||
| 409 |
3 29/32 x 1 1/8 x 2 3/4 |
4 |
||
| 700 |
1 15/16 x 1 1/8 x 19/32 |
2 |
||
| 703 |
2 19/32 x 2 7/16 x 27/?? |
3 |
||
| 734 |
3.9 x 3.0 1.15 |
3 |
||
| 750 |
2 5/16 x 1 11/32 x 1? |
3 |
||
| 751 |
2 5/16 x 2 x 11/16 |
3 |
||
| Misc |
||||
| 3R25, AD28, H1176 |
36 x 96 x 106 1.42 x 3.78 x 4.17 |
3 |
4.5 |
|
| 3R12 (MN1203, 3R12G, 3LR12, 3R12R, 1289) |
22 x 67 x 62 0.87 x 2.64 x 2.44 |
3 |
4.5 |
|
Batery Size1 Table from ASA C18.1-1954, UDC 621.352.7
omitting volume, and Mercury batteries. Ordered highest volume to lowest.| Cell |
Dia in |
Hi in |
Vol 2 cu in |
| No. 6 |
2.5 |
6 |
29.3 |
| J |
1.25 |
5.875 |
7.2 |
| G |
1.25 |
4 |
7.92 |
| F |
1.25 |
3.4375 |
4.22 |
| D |
1.25 |
2.25 |
2.76 |
| CD |
1 |
3.1875 |
2.51 |
| CL |
0.9375 |
2.625 |
1.81 |
| C |
0.9375 | 1.8125 |
1.25 |
| B |
0.75 |
2.125 |
0.95 |
| BR |
0.75 | 1.5 |
0.66 |
| BF |
0.75 | 1.3125 |
0.58 |
| A |
0.625 |
1.875 |
0.57 |
| AA |
0.53125 |
1.875 |
0.42 |
| AAA |
0.390625 |
1.6875 |
0.20 |
| R |
0.53125 | 1.3125 |
0.292 |
| N |
0.4375 |
1.0625 |
0.169 |
| NS |
0.4375 | 0.75 |
0.113 |
Note 2: The energy in a cell is to a first order approximation proportional to it's volume. A second order approximation would subtract some constant so as the total volume decreases the useable volume decreases even faster.
Energizer E95 Alkaline "D" cell is 1 5/16" dia x 2 3/8" hi
Energizer"AA" cell is 9/16" dia x 1 15/16" hi
No. 6 Dry Cell is 2 ½" dia x 6" tall
The tab unit cell for my 2AA Pocket Flash Lights needs to be less than 0.7" some fractions that would work: <= 5/8, 21/32 (23/32 very tight), 45/64. The 700 is 19/32 which is thin enough by 1.9375" wide by 1 1/8. If the 1 1/8 is just the body and the tabe stick up the right distance it would fiy my wide Pocket Flash Light. But it's 2 cells which might burn out the lamp?
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This Flash Light battery is 2 5/8" x 1 3/8" x 3/4". Note 3/4" is just the size to fit the Eveready Pocket Flash Lights. The 1 3/8" dimension, the width in the photo would be just right for the narrow Pocket F.L.. That leaves the 2 5/8" height which would be too tall. 2 1/2" is also too tall. 2 1/4 or 2 1/8 high would work.
It may be that these very early batteries had a lot of internal
resistance, so although they measured 3 volts open circuit, when
connected to the lamp the actual voltage across the lamp was less than
3.0 volts. I feel that connecting two modern 3 volt Alkaline
cells to the lamp would burn it out.
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This Eveready Pocket Flash Light has a No. 750 battery installed. The 750 is a three cell battery with dimensions of 2 5/16 x 1 11/32 x 1? You can see at the top left of the battery the short tab is making contact with the tab connected to the switch. That makes a circuit to the case which in turn is connected to the threaded part of the lamp. The tip of the lamp makes contact to the long battery tab that's folded flat across the top of the battery. So as shown the light would be on. But the switch is shown in the up position which should be off, so either the switch tab or battery tab would need to be bent so they are not touching when the switch is all the way up. The U shape metal that's part of the switch is there to hold the battery to the right. 1053390 Galvanic Cell , Albrecht Heil (Conrad Hubret & Samuel Stern), Feb 18 1913, 429/224 ; 429/229 - Manganic Hydrate as depolarizer gives 1.6 Volt cell 1053505 Galvanic Cell, Albrecht Heil (Conrad Hubret & Samuel Stern), Feb 18 1913, 429/224 ; 429/229 - Manganese Dioxide as depolarizer gives 1.7 Volts per cell. | Printed on Front No. 750 Eveready Tungsten Battery Highest Grade Battery in the World American Eveready Works of National Carbon Co Inc Long Island City, N.Y. Chicago Atlanta San Francisco Patented Feb 18 1913 |
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Here the battery is installed the correct way around. The switch is a little below the half way point and the circuit is open. If the switch is pushed up the circuit will be closed. It looks like red sealing wax has been poured into the top of the battery and there's still an eighth of an inch of battery wrapper exposed. For a battery that's probably 90 years old it's held up fairly well. | Printed on Back Guarantee We guarantee this tungsten battery to give 1 to 2 hours service when used with an Eveready Mazda bulb. IMPORTANT Bulbs are expecially designed for use with tungsten batteries and will give the highest efficiency for your protection The name eveready is stamped on the base Side: The original and only battery of quality. Other side: Guarantee expires 4 23 price 30 cents |
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 The carbon rods and their caps can clearly be seen.The sheet metal tabs are just soldered to the two cells. All the wiring is at the top and both cells are installed positive end up. X-ray by my dentist Dr. John Scoggins at Park Falls Dental. The solid state X-ray makes an image that's life size and covers 36 x 25.6 mm i.e. the same size as a full frame 35mm camera negative. The resolution is 635 pixels per inch or 25 pixels per mm. Each pixel is an 8 bit gray scale value. |
The size is very slightly larger that two AA batteries side by side. The tabs are about 0.011" thick and very springy. The top looks like it has had sealing wax poured into it. |
 The symbol at right may be a Franco logo? |
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 Eveready Shield Mark on Eveready No. 750 Pocket Flash Light. Center has overlaid E and R. |
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Two AA Battery Adapter to replace No. 750 This was the first try at making battery adapter patterned after the one by Bill Utley in the Flashlight Collectors Newsletter. But instead of using a huge pop rivet I'm using an eyelet. But a problem showed up after the first phosphor bronze spring was attached. It's that there is nothing to keep it from turning, as shown in the image to the left. The real batteries have both tabs well located in rotation. Now working on a way to fix the tabs rotation. |
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Two AA Battery Adapter to replace No. 750 ver 2
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Eveready No. 751 Pocket Flash Light Battery |
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2 1/4 hi x 5/8 thick x 1 15/16 w |
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| You can feel three cells under the paper. Lamp in Pocket Flash Light is marked 3.6 V |
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Same patent date Feb 18 1913 as No. 750 above 1053390 Galvanic Cell 1053505 Galvanic Cell |
 Guarantee Expires 3 27 |
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| Franco No. 1041 3 AA Pocket Flash Light battery | ||
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MN1203 aka 3R12 4.5 Volt Battery2 3/8" wide x 2 1/2" hi x 27/32" thick. 6 ounces.
The tabs are made out of a dead soft metal and do NOT have spring action and so do not make good contact with the lamp base. Because of the poor spring action this battery requires some "fiddiling" to get it to work. Or that may be just the nature of this type of battery? |
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 Petrix Pocket Flash Light On using MN1203 battery. |
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Franco Dec 29 1914 1122777 also works with MN1203.  |
738025 Dry-Cell Battery, Edwin R. Gill (Electric Contract Co ECCO), Sep 1, 1903, 429/166 ; 429/229 - pointed carbon allows better packing prior to inserting carbon
777457 Battery Case, Wappler, Dec 1904, 429/99 ; 429/159; 439/500 - a box to hold a number of series connected cylindrical cells
880703 Battery, George M. Wheeler, 429/159 ; 206/705; 429/178 - Pocket Flash Light, repairable
1053390 Galvanic Cell , Albrecht Heil (Conrad Hubret & Samuel Stern), Feb 18 1913, 429/224 ; 429/229 - Manganic Hydrate as depolarizer gives 1.6 Volt cell
1053505 Galvanic Cell, Albrecht Heil (Conrad Hubret & Samuel Stern), Feb 18 1913, 429/224 ; 429/229 - Manganese Dioxide as depolarizer gives 1.7 Volts per cell.
1011992 Dry Battery, D.L. Ordway (National Carbon Co), Dec 19, 1911, 429/159 - multi-cell prismatic Ignition Battery high Watt hours/cu inch
1066280 Protective Container for Dry Batteries, Kaempfer, Jul 1913, 206/705 ; 229/102; 229/81 - a box to hole a pocket flash light battery with holes for testing and a seal so bettery can not be exchanged with a dead one.
1090624 Casing for Electric Cells, I. Kaempfer, Mar 1914, - for cylindrical cells
1292764 Dry Cell and it's Method of Manufacture, Hambuechen (Burgess Battery), Jan 28 1919, 29/623.1 -
1303558 Battery Cell, Harry T. Hipwell, May 13, 1919, 429/65 ; 206/705; 429/167 - method of making cell easy to ship (used in speed flash)
1307868 Flash Light Battery, A.S. Lynne, Jun 24 1919, 429/166 ; 429/157 - one piece zinc cup, no leaks & same size
instead of soldering a flat sheet into a cylinder then soldering a bottom cap, form the cup from a single piece of zinc
1316597 Dry Cell, Schroger (Burgess Battery), Sep 23 1919, 429/132 ; 429/137; 429/229 - 1331877 Electric Battery, O.E. Ruhoff, Feb 24 1920, -
1398518 Flashlight-Battery, H.H. Hipwell, Nov 29, 1921, 429/133 ; 429/142; 429/247 - use rubber band to hold core cover cloth in place instead of thread
1590873 Primary Cell, UNION DRY BATTERY CORP
1760090 Dry Cell
1836847 Dip for Dry Cell Cores, JOSEPH M. HENDERSON (Burgess Battery), Dec 15, 1931, 429/232-
1839498 Dry Cell, H. W. FORTH (Burgess Battery), Jan 5, 1932, 429/166 ; 429/202; 429/229-
1856386 Primary Battery, (National Carbon Co), G. W. HEISE, May 3, 1932, 429/220 ; 429/229 - High Current Applications
has some technical data, for miner's lamps
1858026 Battery, Schulte (Burgess Battery), May 10 1932, 429/159 ; 362/171; 429/178 - metal can for pocket flash light battery1874376 Process of Making Dry Cells, W. D. STALEY, Aug 30, 1932, 29/623.5 ; 427/113; 427/443.2; 429/301
1214916 Lamp, Ellsworth A. Hawthorne (Hawthorne Co), Feb 6, 1917, 362/375 - bicycle tail light
Hawthorne made carriage, bicycle lights
and lanterns. A quick connect pipe clamp mount for a spot
light allowed carriage
mountion or to about anything round.
2710887 Method of Sealing Dry Cells and Sealed Dry Cell Construction, Albert Gelardin, Jun 14, 1955, 429/172 - mountion or to about anything round.
References:
2025028 Dry Cell, Fausek, Dec 24 1935, 429/173 -
2289249 Dry Cell Battery, C. P. DEIBEL, Jul 7 1942,429/54 ; 174/521; 429/168 -
2307763 Dry Cell Battery, Cyril P. Deibel, Jan 12, 1943, 429/168 ; 429/185; 429/86 -
2546379 Dry Cell and Method of Making same, Woodring, Mar 1951, 429/170 -
2636063 Electrical Battery, Walter W. Schroeder (Sprague), Apr 21, 1953, 429/54-
2826681 Multicell Battery, H.R.C. Anthony (Electric Storage Battery Co), Mar 11 1958, 362/194 ; 429/158; 429/174 -2025028 Dry Cell, Fausek, Dec 24 1935, 429/173 -
2289249 Dry Cell Battery, C. P. DEIBEL, Jul 7 1942,429/54 ; 174/521; 429/168 -
2307763 Dry Cell Battery, Cyril P. Deibel, Jan 12, 1943, 429/168 ; 429/185; 429/86 -
2546379 Dry Cell and Method of Making same, Woodring, Mar 1951, 429/170 -
2636063 Electrical Battery, Walter W. Schroeder (Sprague), Apr 21, 1953, 429/54-
2879315 Vented Sealed Dry Cell Construction, Albert Gelardin, Mar 24 1959, 429/82 ; 429/172 -
3874932 Dry Cell, Yoshio Uetani
RE30458 Dry Cell, Yoshio Uetani, Dec 23, 1980
William F. Hendry - many many Dry Cell patents Optics
The light leaves the bulb in all directions. Some may go to the reflector and where it goes next depends on if the filament is at the reflector focus. Some light will never touch the reflector and instead goes out the end of the device. If there's a lens then if the filament is at the focal point of the lens that light will be collimated, i.e. it will go in a parallel bundle of light. The very common Edison 10 mm miniature screw based (E10) lamps do not control the location of the filament and so are almost never focused as installed. That's why there are many patents on ways to focus the light.The very early flash lights used white paint on a parabolic reflector. Later some used silver reflectors, these look great when silver polish is used. Later some shiny metal (Chrome, Nickel ?) was plated on a brass reflector. Still later metal was applied to plastic to make the reflector.
In the case of a flashlight with a reflector and flat glass or the case of the reflector and lens the light that goes froward from the lamp makes a wide beam and the light that's reflected then goes forward makes a narrow beam. In some cases, like in smoke or fog, it's good to eliminate the wide beam which is weaker than the narrow beam so that back scattered light is reduced thus increasing visibility. The Hipco dual lens flashlight does this. There are other flashlights that get a similar, but not as good, effect by blocking some of the forward light with an obstruction directly in front of the lamp. For example the Smoke Cutter made by G.T. Price.
There's a good explanation of the dual lens optical system in a patent for an allergy pollen sensor.
5986555 Allergen Detector System and Method, Robert M. Hamburger, 340/627, Nov 16 1999 - two lens system and includes central obstructions to block laser beam.
524075 Reflector for Electric or Other Lamps, ERNEST TILMANN, Aug 7, 1894, 184/5 - two parabolic on common axis
1169819 Process for Preparing Metalic Filaments, ROBERT H. HENDERSON (Westinghouse), Feb 1, 1916, 219/149 ; 148/576; 72/364 - multistage drawing
1211447 Lantern Lens, L.J. Houze, Jan 9 1917, 362/333 -
2136237 Method and Apparatus for Prefocusing Lamps, D.E. Ekmendorf (GE), November 8, 1938, 445/64 ; 250/201.1; 250/234; 250/554; 318/264; 318/283; 318/480; 318/54; 356/400; 361/175; 362/296 - Vacuum tube and electric motors position filament. Automobile headlight app.
2469080 Unitary Lens, S. Rosin, May 3 1949 362/327 ; 353/102; 359/724; 359/727; 362/336- combines reflection and refraction to make narrow beam - many patents reference this one.
D31588 Lantern Reflector, Frank Rhind, Oct 3 1890, D26/128 -
Switch & Wiring
Conrad's first flash lights were made
using fiber tubes which are insulators. That makes it easy to
bring out two terminals which when connected turn on the light.
The big problem with that is when the switch is in the off position and
any metal touches the two terminals (like in a tool box) the light is
turned on and the batteries go dead. The user later takes the
light out of his tool box and the switch is clearly off, but the
batteries are dead. Seem like those batteries don't last very
long.
Many early switch & wiring designs were aimed at preventing the above problem.
It's relatively easy to make a push button switch that normally off and momentarily on, the nomenclature is: OFF-(ON). But it's more difficult to make a switch that is positivitily off, allows momentary push button operation and has an always on position that allows you to put the light down and use your hands for something else.
A further refinment is to place the switch somewhere so that it's very easy to use allowing full operation of the flashlight with one hand.
Many early switch & wiring designs were aimed at preventing the above problem.
It's relatively easy to make a push button switch that normally off and momentarily on, the nomenclature is: OFF-(ON). But it's more difficult to make a switch that is positivitily off, allows momentary push button operation and has an always on position that allows you to put the light down and use your hands for something else.
A further refinment is to place the switch somewhere so that it's very easy to use allowing full operation of the flashlight with one hand.
