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Archive for February 6th, 2019

Juki TL-2010Q: COB LED Light Levels

The COB LED module claims to run at 12 V and 6 W, so it expects to draw 500 mA. First pass measurements showed 500 mA happened at 11.6 V:

Juki TL-2010Q COB LED - ballast resistor test
Juki TL-2010Q COB LED – ballast resistor test

The 12 VDC supply actually produced 12.1 V at 500 mA, so a 1 Ω 1/2 W resistor should produce the right current:

Juki TL-2010Q COB LED - heatsink endcap - internal connections
Juki TL-2010Q COB LED – heatsink endcap – internal connections

Which it did, but the Customer Base judged 6 W to be far too much light. A 2.7 Ω resistor seemed too dim, so we settled on 2.2 Ω:

Juki TL-2010Q COB LED - 2.2 ohm header
Juki TL-2010Q COB LED – 2.2 ohm header

For the record, a 2.2 Ω resistor drops 980 mV and dissipates 440 mW, probably too close to its 500 mW rating. The supply produces 12.2 VDC at 450 mA, so the LEDs run at 11.2 V and dissipate 5 W; the heatsink remains pleasantly warm to the touch.

The hot melt glue anchoring the pin header won’t win any prizes, but it sticks like glue to the Kapton tape and, in any event, there’s not much to go wrong in there.

A cardboard cover hides the ugly details:

Juki TL-2010Q COB LED - installed
Juki TL-2010Q COB LED – installed

And then It Just Works™:

Juki TL-2010Q COB LED - installed - rear view
Juki TL-2010Q COB LED – installed – rear view

As evidenced by the glove fingertips, she does a lot of sewing and I’m glad I can shed some light on the subject …

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