[BC] Vetta TSL-C 20 LED lamp somewhat, tho imperfectly, regulated:
martygoodman
USE a NON PROPORTIONAL font (such as Courier) to display these tables,
Analysis of Vetta TSL-C 20 LED tail lamp:
High Power Continuous On Mode:
[NOTE that between 4.0 volts and 7.0 volts the apparant brightness of the
beam DID NOT CHANGE PERCEPTIBLY during this test. I tried flicking my power
supply voltage back and forth, between 4.5 and 6.8 volts, and did NOT notice
the lamp to visibly change in brightness.]
Volts Amps Watts
----- ---- -----
3.5 .08 0.28
4.0 .39 1.56
4.2 .41 1.72
4.6 .39 1.79
4.8 .38 1.82
5.0 .37 1.85
5.2 .36 1.87
5.4 .36 1.94
5.6 .35 1.96
5.8 .35 2.03
6.0 .36 2.16
6.2 .36 2.23
6.4 .35 2.24
6.6 .34 2.24
6.8 .33 2.24
7.0 .33 2.31
As the lamp was visibly as bright at 4.5 volts as at 6.5 volts, and as it
consumed about a half a watt LESS at 4.5 volts, I have to judge the
VistaLite TSL-C to be somewhat, but poorly, regulated. The lamp is about 25%
more efficient when run at 4.5 volts than at 6.5 volts, this would seem to
indicate, given the relative 1.75 vs 2.24 watts of power consumed at those
two voltages, and the apparant equal light output at both voltages.
Clearly this is not carefully-constructed DC to DC high efficiency current
regulator. It apperas to behave to some extent like a linear regulator, but
not quite: Current DOES decrease as the voltage is increased, but it
decreases too little for really good, tight regulation.
This moderate degree of regulation, however, is better than none, by far.
Low Power Continuous on Mode:
volts amps watts
---- ---- -----
4.0 .11 .44
4.5 .10 .45
5.0 .09 .45
5.5 .09 .50
6.0 .09 .54
6.5 .09 .59
7.0 .08 .56
The pattern is similar here to that with the lamp in high power mode.
Again, the lamp (which is about as bright at 4.5 volts as it is a 6.5 volts)
is about 25% less efficient (actually closer to 30% less efficient here) at
the higher voltage.
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