Lamp Bulb Question????

[Brian Baker]

Hello,

Can anyone tell me the difference between W (watt) and cp (candle power)? Are these interchangeable? The workshop manual has them listed as W (Europe) and cp (USA).

My '69 911 light housings are stamped as such: turn signal 21W 32cp, reverse 18W 15cp. On my driver's side I have an 1156 bulb in both slots but on the passenger side I have an 1156 in the turn signal and a 1073 in the reverse. The bulbs are the same size but I know that the W or cp is different for each. I can't seem to find an over the counter 1073 anywhere.

My car has a mixed nuts assortment of bulbs from Germany, Hungary, USA and China. They all have different numbers and some have no numbers at all. All I want to do is buy all new bulbs that match and are the correct W or cp. Is there such a thing as a universal bulb exchange chart I could download? Sort of like a currency exchange rate.

Thanks for your help.

Brian

[kees]

Some light sources such as flashlights are rated in various different units, such as candlepower or watts. To be able to compare different types of light sources, it would be necessary to convert between these types of units.

The short answer is, you cannot. Unless the manufacturer already has calculated both candlepower and watts, you're pretty much out of luck. You could try searching review sites in addition to the manufactures site, in hopes of finding the information already calculated.

Different light sources could have the same power requirements, but vastly different light output. They are just not directly related enough.

For example, searching Amazon.com I found descriptions of two different 12,000 candlepower flashlights. One was listed as 3 watt and another listed as 1 watt.

Here are the definitions of some units:

candlepower
One candlepower is the radiating power of a light with the intensity of one candle. This unit is considered obsolete as it was replaced by the candela in 1948, though it is still in common use. 1 candlepower is equal to about 0.981 candela. *

candela
The standard unit for measuring the intensity of light. The candela is defined to be the luminous intensity of a light source producing single-frequency light at a frequency of 540 terahertz (THz) with a power of 1/683 watt per steradian, or 18.3988 milliwatts over a complete sphere centered at the light source. *

lumen
The standard unit for measuring the flux of a light being produced by a light source. One lumen represents the total flux of light emitted, equal to the intensity in candelas multiplied by the solid angle in steradians (1/(4·pi) of a sphere) into which the light is emitted. *

[nesslar]

www.sylvania.com!..... "17 1073 S.C. Bayonet BA 15s 12.8 1.8 32 C-6 200 20"......
Yep, 1073! They show all their automotive lighting in their electrocic catalog.
Now you can find an array of bulbs to make things right.