Don's bulbs
rare light bulbs and lamps
glossary of termsinformation


Variations in candlepower, current, total watts, and watts per candlepower with variations in voltage of drawn-wire tungsten filament are shown in graph form.

Also see re-rating.

Candlepower, current, and total watts increase slightly with an increase in voltage, and watts per candlepower decreases.

In other words, the higher the voltage, the higher will be the current, the candlepower and total watts, and lower will be the watts per candle.

In obtaining values from this chart, it is necessary to go to the VOLTS curve first.

For example to ascertain conditions at 105 percent of normal voltage, the vertical line beginning midway between 100 and 110 at the bottom of chart is followed until it intersects with volts curve.

Then, by following to the left along the horizontal line from point of intersection, CANDLEPOWER of 120 percent is obtained.

The same horizontal line intersects with 90 percent of WATTS PER CANDLE, and AMPERES at 103 percent, with WATTS consumed being 108 percent.

reference for this page: CHARACTERISTIC CURVES

reference to this page: RE-RATE