presents a led down lighter, emitting cold white light. The lamp has an external power supply that converts the 230 V AC into a direct current for the leds.

This article shows the measurement results. Many parameters are also found in the Eulumdat file.

See this overview for a comparison with other light bulbs.

Summary measurement data

parameter	meas. result	remark
Color temperature	13396 K	Very cold white
Luminous intensity Iv	271 Cd	Measured straight underneath the lamp.
Illuminance modulation index	14 %	Measured straight underneath the lamp. Is a measure for the amount of flickering.
Beam angle	80 deg	80º for all C-planes since the lamp is symmetrical along its 1st axis.
Power P	21.3 W
Power Factor	0.96	For every 1 kWh net power consumed, there has been 0.4 kVAhr for reactive power.
THD	7 %	Total Harmonic Distortion
Luminous flux	526 Lm
Luminous efficacy	25 Lm/W
CRI_Ra	80	Color Rendering Index.
Coordinates chromaticity diagram	x=0.2725 and y=0.2657
Fitting	230V	This lamp is via an external power supply connected to the 230 V grid voltage.
PAR-value	3.0 μMol/s/m2	The number of photons seen by an average plant when it is lit by the light of this light bulb. Value valid at 1 m distance from light bulb.
PAR-photon efficacy	0.3 μMol/s/We	The toal emitted number of photons by this light, divided by its consumption in W. It indicates a kind of efficacy in generating photons.
S/P ratio	2.6	This factor indicates the amount of times more efficient the light of this light bulb is perceived under scotopic circumstances (low environmental light level).
D x H external dimensions	171 x 165 mm	External dimensions of the lamp.
D luminous area	139 mm	Dimensions of the luminous area (used in Eulumdat file). This is the surface of the milk white plate at the front side.
General remarks		The ambient temperature during the whole set of measurements was 22.1-22.3 deg C. The temperature of the housing gets about 35 degrees hotter than ambient temperature. Warm up effect: during the warm up time the illuminance decreases with 7 % and the consumed power with 7 %. Voltage dependency: the power consumption and illuminance vary insignificantly, when the power voltage varies between 200-250 V.
Measurement report (PDF)
Eulumdat file		Right click on icon and save the file.

Overview table

The overview table is explained on the OliNo website.

Please note that this overview table makes use of calculations, use this data with care as explained on the OliNo site. E (lux) values are not accurate, when within 5 x 139 mm ≈ 700 mm. Within this distance from the lamp, the measured lux values willl be less than the computed values in this overview as the measurements are then within the near field of the lamp.

Eulumdat light diagram

This light diagram below comes from the program Qlumedit, that extracts these diagrams from an Eulumdat file. It is explained on the OliNo site.

The light diagram giving the radiation pattern.

It indicates the luminous intensity around the light bulb. All the planes give (almost) the same results as the lamp is symmetrical along its 1st axis.

Illuminance Ev at 1 m distance, or luminous intensity Iv

Herewith the plot of the averaged luminous intensity Iv as a function of the inclination angle with the light bulb.

The radiation pattern of the light bulb.

This radiation pattern is the average of the light output of the light diagram given earlier. Also, in this graph the luminous intensity is given in Cd.

These averaged values are used (later) to compute the lumen output.

Intensity data of every measured turn angle at each inclination angle.

This plot shows per inclination angle the intensity measurement results for each turn angle at that inclination angle. There normally are differences in illuminance values for different turn angles. However for further calculations the averaged values will be used.

When using the average values per inclination angle, the beam angle can be computed, being 80º for all C-planes looked at.

Luminous flux

With the averaged illuminance data at 1 m distance, taken from the graph showing the averaged radiation pattern, it is possible to compute the luminous flux.

The result of this computation for this light spot is a luminous flux of 526 Lm.

Luminous efficacy

The luminous flux being 526 Lm, and the power of the light bulb being 21.3 W, yields a luminous efficacy of 25 Lm/W.

Electrical properties

A power factor of 0.96 means that for every 1 kWh net power consumed, a reactive component of 0.3 kVAr was needed.

Lamp voltage	230 VAC
Lamp current	96 mA
Power P	21.3 W
Apparent power S	22.1 VA
Power factor	0.96

Of this light bulb the voltage across ad the resulting current through it are measured and graphed. See the OliNo site how this is obtained.

Voltage across and current through the lightbulb

This waveforms have been checked on requirements posed by the norm IEC 61000-3-2:2006 (including up to A2:2009). See also the explanation on the OliNo website.

Harmonics in in the current waveform and checked against IEC61000-3-2:2006

There are no limits for the harmonics for lighting equipment <= 25 W.

The Total Harmonic Distortion of the current is computed as 7 %.

Temperature measurements lamp

Zoomed in on side and bottom view.

The surfaces of the power supply and the heatsink of the lamp itself (heatsink lamp left side and power supply right side) are rough and the masking tape to have a high emissivity was not needed; these materials have a high emissivity of about 0.95. This is a good sign and indicates that these are adapted to radiate heat away. The metal material on the side of the lamp differs in emissivity somewhat from the masking tape (the tape is visible) and therefore this temperature is measured with help of the tape. See below for the in emissivity adjusted image, it appreas that 0.75 is the correct value.

status lamp	> 2 hours on
ambient temperature	21.5 deg C
reflected background temperature	21.5 deg C
camera	Flir T335
emissivity	0.95 and 0.75(1)
measurement distance	0.5 m
IFOVgeometric	0.7 mm
NETD (thermal sensitivity)	50 mK

⁽¹⁾ See the text for explanation.

Color temperature and Spectral power distribution

The spectral power distribution of this light bulb, energies on y-axis valid at 1 m distance.

The measured color temperature is about 13400 K which is very cold white.

This color temperature is measured straight underneath the light bulb. Below a graph showing the color temperature for different inclination angles.

Color temperature as a function of inclination angle.

The measurement of CCT is measured for inclination angles up to 80º. Beyond this angle the illuminance is very low (< 5 lux).

The beam angle is 80º, meaning a 40º inclination angle. In this area most of the light is present. The variation in correlated color temperature in this area is about 7 %.

PAR value and PAR spectrum

To make a statement how well the light of this light bulb is for growing plants, the PAR-area needs to be determined. See the OliNo website how this all is determined and the explanation of the graph.

The photon spectrum, then the sensitivity curve and as result the final PAR spectrum of the light of this light bulb

parameter	value	unit
PAR-number	3.0	μMol/s/m²
PAR-photon current	5.9	μMol/s
PAR-photon efficacy	0.3	μMol/s/W

The PAR efficiency is 70 % (valid for the PAR wave length range of 400 – 700 nm). So maximally 70 % of the total of photons in the light is effectively used by the average plant (since the plant might not take 100 % of the photons at the frequency where its relative sensitivity is 100 %).

S/P ratio

The S/P ratio and measurement is explained on the OliNo website. Here the results are given.

The power spectrum, sensitivity curves and resulting scotopic and photopic spectra (spectra energy content defined at 1 m distance).

The S/P ratio is 2.6.

More info on S/P ratio can be found on the OliNo website.

Chromaticity diagram

The chromaticity space and the position of the lamp’s color coordinates in it.

The light coming from this lamp is outside the area of class A (blue hue). This is an area defined for signal lamps, see also the OliNo website.

Its coordinates are x=0.2725 and y=0.2657.

Color Rendering Index (CRI) or also Ra

Herewith the image showing the CRI as well as how well different colors are represented (rendered). The higher the number, the better the resemblance with the color when a black body radiator would have been used (the sun, or an incandescent lamp). Practical information and also some critics about the CRI can be found on the OliNo website.

Each color has an index Rx, and the first 8 indexes (R1 .. R8) are averaged to compute the Ra which is equivalent to the CRI.

CRI of the light of this lightbulb.

The value of 80 is equal to the value 80 which is considered a minimum value for indoor usage.

Note: the chromaticity difference is 0.010 indicates the distance to the Planckian Locus. There is no norm yet that states what the max deviation from white light is allowed to be. A reference with signal lights as a reference is given in the chromaticity diagram.

Voltage dependency

The dependency of a number of lamp parameters on the lamp voltage is determined. For this, the lamp voltage has been varied and its effect on the following light bulb parameters measured: illuminance E_v [lx], the lamppower P [W] and the luminous efficacy [Lm/W].

Lamp voltage dependencies of certain light bulb parameters, where the value at 230 V is taken as 100 %.

The illuminance and consumed power vary insignificantly when the voltage is varied.

When the voltage at 230 V varies with + and – 5 V, then the illuminance varies < 0.2 %, so when abrupt voltage changes occur this effect is not visible in the illuminance output.

Warm up effects

After switch on of a cold lamp, the effect of heating up of the lamp is measured on illuminance E_v [lx], the lamppower P [W] and the luminous efficacy [lm/W].

Effect of warming up on different light bulb parameters. At top the 100 % level is put at begin, and at bottom at the end.

The warm up time is about 30 minutes, during which the illuminance decreases with 7 % and the consumed power with 7 %.

Measure of flickering

An analysis is done on the measure of flickering of the light output by this light bulb. See the OliNo site for more information.

The measure of fast illuminance variation of the light of the light bulb

parameter	value	unit
Flicker frequency	100	Hz
Illuminance modulation index	14	%

The illuminance modulation index is computed as: (max_Ev – min_Ev) / (max_Ev + min_Ev).