Hi Guys,
Er, what I am is paranoid... 😉
Actually, I am from the UK which accounts for the centigrade temperature scale, but once upon a time I was both a physicist and an EE until I became disillusioned with the academic establishment in the UK.
Now I work as a computer consultant in NY.
As for ability - I am no better than anybody else here and am still in the process of learning from everybody else. It's the ideas that matter, and the communication of those ideas is what causes progress. There are SO many fantastic ideas shared here. Its unbelievable.
My problem is that I talk more authoratatively than most. I am no more intelligent, though.
Bill.
Er, what I am is paranoid... 😉
Actually, I am from the UK which accounts for the centigrade temperature scale, but once upon a time I was both a physicist and an EE until I became disillusioned with the academic establishment in the UK.
Now I work as a computer consultant in NY.
As for ability - I am no better than anybody else here and am still in the process of learning from everybody else. It's the ideas that matter, and the communication of those ideas is what causes progress. There are SO many fantastic ideas shared here. Its unbelievable.
My problem is that I talk more authoratatively than most. I am no more intelligent, though.
Bill.
eebasist said:
I hadn't really thought too much about cooling. I assumed that also would be engineered into the fixture already. I'd further assumed that putting 400w into a fixture engineered for 1000w would allow plenty of thermal 'headroom'.
I haven't received the light yet, and am not sure how to tell the distance to lens 1 from the pictures (or if you CAN!), but the overall length appears to be ~ 3-4 feet. Guess I'll have to just wait to see.
well yes and no it is built into the design of the fixture...... Stage lights get very very very hot. They are made out of thick metal, but they get very hot.......just brushing up against one after its been on will easily burn. I know I'm going to go that route, but need some type of active cooling just havent made it there yet.
Yeah, thats a good point that I forgot about. MH is definitly cooler......the problem with ellipsoidals is there is no real air movement around the bulb because of the reflector and lens assembly.
Heat and wattage
Someone please correct me if I'm wrong, but a 400W halogen will produce the same heat as a 400W MH. The only difference is light yield. The same power (watts) is consumed and dissipated by both.
Someone please correct me if I'm wrong, but a 400W halogen will produce the same heat as a 400W MH. The only difference is light yield. The same power (watts) is consumed and dissipated by both.
Nope, they wont produce the same amount of heat. They both take 400W of energy, however more of that energy is converted to light than heat with a MH. Its more efficient use of the energy....unless you wanted heat and not light to come from it
mycamel,
Power consumed is the same, but how that power is dissipated is not...
Halogens dissipate virtually all the power as heat: thermal "friction" due to the electrons flowing through the filament cause it to get very hot - usually to around 2800K.
That heat is transmitted: through conduction along the support for the filament back into the bulb housing; as convection of air currents; and as radiant "light" energy (em radiation).
The radiant light energy effectively follows the standard black-body response curve which means that most of the light emitted at this temperature falls into the infra-red band. This kind of light interacts with matter to induce thermal vibrations at an atomic/molecular level and hence causes heat. Only some of the radiant light energy exists in the visible band.
This is the origin of "colour temperature", a term which describes the apparent colour of a black body at the given temperature.
MH, MV, Sodium and Fluorescent discharge bulbs all work a diifferent way: the flow of electrons through the gas of the bulb DOES cause some heating, but the dominant effect is that the energy carried by the electrons, accelerated through the applied electric field, gets transferred to the electrons of the gas. The excited electrons of the gas then, triggered by some means or other, "discharge" to a lower energy level, emitting em radiation of a specific frequency, or a combination of frequencies.
This emitted em radiation (light energy) is either usable directly (MH, MV, Sodium), or needs to be passed through some kind of fluorescent material to produce visible light (the mechanism of the fluorescent tubes).
This discharge mechanism is much more efficient at producing light in the visible spectrum than the thermal mechanisms.
Thus, for every watt consumed, there will be more usable visible light, and less "heat".
Incidentally, the different gasses used for the discharge bulbs tend to produce specific emission frequencies: in the fluorescent tubes, the emission is UV; in the MH bulbs, the emission contains a decent balance of red, green and blue components compatible both with or eyes, and with projection technology; MV bulbs produce a set of frequencies that our eyes can use within limits, but are dominated by the green component, and are not compatible with the RGB filters that projectors use; Sodium bulbs produce variations on a theme of yellow...
This is the origin of the Colour Rendering Index (CRI) that people also talk about...
Bill.
Power consumed is the same, but how that power is dissipated is not...
Halogens dissipate virtually all the power as heat: thermal "friction" due to the electrons flowing through the filament cause it to get very hot - usually to around 2800K.
That heat is transmitted: through conduction along the support for the filament back into the bulb housing; as convection of air currents; and as radiant "light" energy (em radiation).
The radiant light energy effectively follows the standard black-body response curve which means that most of the light emitted at this temperature falls into the infra-red band. This kind of light interacts with matter to induce thermal vibrations at an atomic/molecular level and hence causes heat. Only some of the radiant light energy exists in the visible band.
This is the origin of "colour temperature", a term which describes the apparent colour of a black body at the given temperature.
MH, MV, Sodium and Fluorescent discharge bulbs all work a diifferent way: the flow of electrons through the gas of the bulb DOES cause some heating, but the dominant effect is that the energy carried by the electrons, accelerated through the applied electric field, gets transferred to the electrons of the gas. The excited electrons of the gas then, triggered by some means or other, "discharge" to a lower energy level, emitting em radiation of a specific frequency, or a combination of frequencies.
This emitted em radiation (light energy) is either usable directly (MH, MV, Sodium), or needs to be passed through some kind of fluorescent material to produce visible light (the mechanism of the fluorescent tubes).
This discharge mechanism is much more efficient at producing light in the visible spectrum than the thermal mechanisms.
Thus, for every watt consumed, there will be more usable visible light, and less "heat".
Incidentally, the different gasses used for the discharge bulbs tend to produce specific emission frequencies: in the fluorescent tubes, the emission is UV; in the MH bulbs, the emission contains a decent balance of red, green and blue components compatible both with or eyes, and with projection technology; MV bulbs produce a set of frequencies that our eyes can use within limits, but are dominated by the green component, and are not compatible with the RGB filters that projectors use; Sodium bulbs produce variations on a theme of yellow...
This is the origin of the Colour Rendering Index (CRI) that people also talk about...
Bill.
Woooo Woooo ... I'm a Blockhead!
ok...it's Blockhead time...I have an ovp ordered thet has 400 watt 5,500 lummen hallogen bulb...I'm doing the usual thing of trying out the panel (Nview Spectra C) on the overhead first to get my feet wet. I have a dedicated room for this project and I have it completely dark (No outside light what so ever)...For you experts out there will this sufice or do you forsee issues with hallogen heat? -thanks
ok...it's Blockhead time...I have an ovp ordered thet has 400 watt 5,500 lummen hallogen bulb...I'm doing the usual thing of trying out the panel (Nview Spectra C) on the overhead first to get my feet wet. I have a dedicated room for this project and I have it completely dark (No outside light what so ever)...For you experts out there will this sufice or do you forsee issues with hallogen heat? -thanks
Blockhead, you'll be fine as long as you dont have ambient light to work with. 5000 lumens will suffice on a spectra C. What OHP did you get? You will have some heat, but you could raise the LCD panel a bit for more airflow...but to watch DVD's you'll be fine, now watching a movie marathon will start to heat up the room a bit.
Bill, now I remember why I'm not a chemist anymore and getting my MBA.........while i love the sciences, I can't just pull physics like that out of my head anymore.....something about quantum mechanics just really makes me want to cry
eebasist,
luckily we don't need quantum mechanics here, i heard a physist say, 'people who understand quantum mechanics, must be crazy!'
xblocker
luckily we don't need quantum mechanics here, i heard a physist say, 'people who understand quantum mechanics, must be crazy!'
xblocker
just a question
i know this is not an audio forum, but i just wanna know...
do you guys think that KLIPSCH 5.1 surround sound system is worth buying?
thanks
aleksey
i know this is not an audio forum, but i just wanna know...
do you guys think that KLIPSCH 5.1 surround sound system is worth buying?
thanks
aleksey
woneill said:
I plan on building a quantum computer one day...
the harder the formula to process, the faster it will process it...
it will be wicked!
quantum computer.
Hey multiplexor
If you give it a problem that is hard enough will it process it before you finish giving it the problem?
Hey multiplexor
If you give it a problem that is hard enough will it process it before you finish giving it the problem?
woneill,
i would like to, but i only know little about Heisenberg, Penrose and some others, although i was a physics student in my former years. Today siences are just a hobby for me, among others. All i know about quantum mechanics is, it has to do with the influence of measure devices to the measurement itself, e.g. during measurements of photons, which can't precisely defined at a location at a given time.
As far as i know....
xblocker
i would like to, but i only know little about Heisenberg, Penrose and some others, although i was a physics student in my former years. Today siences are just a hobby for me, among others. All i know about quantum mechanics is, it has to do with the influence of measure devices to the measurement itself, e.g. during measurements of photons, which can't precisely defined at a location at a given time.
As far as i know....
xblocker
eebasist,
- The ohp is a Buhl 2963
-what material do you suggest I use to raise the LCD panel and also what ballpark guess would you suggest it be raise (.25 inch .50 inch .75 inch or more?)
Thank you,
Blockhead
- The ohp is a Buhl 2963
-what material do you suggest I use to raise the LCD panel and also what ballpark guess would you suggest it be raise (.25 inch .50 inch .75 inch or more?)
Thank you,
Blockhead