# some light Q

#### iluvflashlight

##### Newly Enlightened
what the different between lux and lumen, what is Wat and what is volt and also why torch that accept 2 cr123a battery cant accept 4 aa battery?
how you all konw that when a adv of light the beam of the light is clearly show how does you make that effect, the last time i saw it was in a really dark and small room where there is 0 light source, furthermore that is just a 1aa battery
lastly thanks for reading through this chunk of text

#### StarHalo

##### Flashaholic

Lumen = total light being emitted
Lux = how far the light goes
Watts = how much energy is being used (Watts = Volts x Amps)
Volt = how much energy could potentially be used (Volts = Watts / Amps)

A flashlight that requires 2x123 batteries needs 6 volts total (one 123 cell is 3 volts, x 2), 4 standard AA batteries are also 6 volts, so as long as you could find a way to connect the batteries, it would work.

how you all konw that when a adv of light the beam of the light is clearly show how does you make that effect, the last time i saw it was in a really dark and small room where there is 0 light source, furthermore that is just a 1aa battery

Can't quite decipher this one, can you clarify?

#### VillageIdiot

##### Newly Enlightened
I think he's asking how to make the beam visible...?

LPF is that way.

#### StarHalo

##### Flashaholic
I think he's asking how to make the beam visible...?

Ah, I think I see it now, ty

You can get a picture of a visible beam of light by using a camera that allows for slow shutter speeds. In a completely dark area, you turn the light on, then with the camera mounted on a tripod (so nothing blurs), take a shot where the shutter remains open for several seconds - the longer the shutter is open, the more light it gathers, and thus the more light there appears to be in an image. The result is a picture where every tiny bit of light is greatly amplified and exaggerated, including light just passing through the air, which gives you a visible beam.

To get a visible beam by the naked eye, you need fog/moisture in the air. Regardless of how weak your light is, if there's enough fog, you'll see the beam plainly, though the more off axis you are (the farther away you are from the beam of light itself), the less brighter it will appear.

#### mdocod

##### Flashaholic
Smoke a few cigarettes in the garage. then try

4AA cells are not always a replacement for 2xCR123, as AA alkaline cell can't really deliver any more than ~1 amp. while CR123s can deliver ~2.5A maximum. So it depends on the bulb in question.

#### BlueBeam22

##### *Super Flashaholic*
Lux is the measurement of a light's beam intensity (focus) from a given distance. Generally, the higher the lux of a light, the farther it will throw.
For example, if you shine two lights side by side at a wall 30 feet away, the light with the brighter hotspot (brightest part of a light's beam) has more lux.
Lumen output is just the measurement of total light output, such as how brightly a light will illuminate a dark room if you shine it at the ceiling.

#### iluvflashlight

##### Newly Enlightened
thanks everyone cpf is indeed a place to learn more on flashlight

#### tebore

##### Flashlight Enthusiast
thanks everyone cpf is indeed a place to learn more on flashlight

We're all willing to help. A word of advice though. There's a lot of in already out there, quick search will help us help you. Plus it makes that much more addictive when you find out more info than you wanted to know. :twothumbs

#### iluvflashlight

##### Newly Enlightened
ya read through most of you guys reply thanks, teabore that thread contain a lot of post, will take my time to read it thanks too

#### artec540

##### Enlightened

Lumen = total light being emitted
Lux = how far the light goes
Watts = how much energy is being used (Watts = Volts x Amps)
Volt = how much energy could potentially be used (Volts = Watts / Amps)

A flashlight that requires 2x123 batteries needs 6 volts total (one 123 cell is 3 volts, x 2), 4 standard AA batteries are also 6 volts, so as long as you could find a way to connect the batteries, it would work.

Can't quite decipher this one, can you clarify?

Lux is lumens per square metre, so its a measure of the distribution, or concentration, or the light.
A volt is a measure of electrical pressure
An ampere is a measure of electrical flow
A watt is a measure of power...... 746 watts = one horse-power.
Ampere-hours (Ah) is the measure of a battery's staying power.

Those are the ones that I find helpful but I expect we all have our own ways of grasping the quantities.......and of course these aren't anything like all of them.

#### okbohn

##### Newly Enlightened
Keep asking questions...only way to learn!

I learn something every time I read here.