5
Fig. 3: Radiant intensity
as a function of temperature
T
6. Changing bulbs
In order to change the bulb, the following equip-
ment is also required:
1 Bulb, 12 V/21 W, socket BA15S
1 Screwdriver
1 Piece of sandpaper
1 Soldering iron
Solder
Unscrew the back of the housing.
Unsolder the bulb.
Sand down the contact surfaces where the
wires are to be soldered to the new bulb and
tin them with solder.
Set the bulb in position and solder it in place.
Test the lamp by applying a voltage of 12 V.
Screw the housing back together.
7. Disposal
Packaging should be
disposed of at local re-
cycling centres.
Should the equipment
need to be scrapped, it
must not be disposed of
in normal household
waste. Local regulations
for the disposal of elec-
trical equipment should
be observed.
8. Appendix
Tab. 3: Specific resistance ρ of tungsten as a function of the absolute temperature
T
and calculated resistance
ratios
R
(
T
)/
R
300
K
or
R
(
T
)/
R
290 K
(see Fig. 1 and Fig. 2)
K
T
m
n
ρ
K
300
R
T
R
K
290
R
T
R
K
T
m
n
ρ
K
300
R
T
R
K
290
R
T
R
K
T
m
n
ρ
K
300
R
T
R
K
290
R
T
R
K
T
m
n
ρ
K
300
R
T
R
K
R
T
R
290
290 54.17
1.000 710 163.86 2.900 3.025 1130 288.49 5.106 5.325 1550 419.46 7.424 7.743
300 56.50 1.000 1.043 720 166.76 2.951 3.078 1140 291.53 5.160 5.381 1560 422.65 7.481 7.802
310 58.84 1.041 1.086 730 169.65 3.003 3.132 1150 294.58 5.214 5.438 1570 425.85 7.537 7.861
320 61.19 1.083 1.130 740 172.55 3.054 3.185 1160 297.63 5.268 5.494 1580 429.06 7.594 7.920
0
2,00E+009
4,00E+009
6,00E+009
8,00E+009
0,000
0,002
0,004
0,006
0,008
0,010
0,012
0,014
0,016
T
4
-5
x10
K
V
