Anyone knows what this black unit is? I probably blew up my extension power board when I plugged in a large load on it this week.
I think it’s a fuse(?). It does have a spring-loaded black button on it. No idea what it does though. Continuity is there across those terminals. I couldn’t find a spare unit in the local electrical shops.
Trying figure out how to fix the extension board. It’s either that black unit or one of the wires melted in the cable coming to it.
The circuit is mostly similar to those in LED bulbs. You have the input protection Metal Oxide Varistors (MOVs), Bridge rectifiers and a cheapo buck LED driver IC MT7844S. The LED strip consists of 100 LEDs (4 Parallel arms with 25 LEDs in series) with an open circuit voltage of around 75V. These LED strips are made on a metal-clad PCB which acts as a heatsink along with the metallic tube to dissipate the heat. The diffuser on top provides even illumination along its length.
These are pretty cheap to manufacture. Since circuitry inside is more or less the same as an LED bulb there will be huge reuse of BOM materials across products(Implying lesser costs). This is also one of the reasons why LED tube lights and LED bulbs(slightly lesser wattage) are sold more or less in the same price bracket.