Dave_H
Flashlight Enthusiast
I thought to start a thread about what's inside ordinary low-cost LED ac bulbs, as I have taking the plastic tops off a number of them. This is usually not a complete teardown, and does not include glass bulbs, such as filament bulbs.
Majority of these use high-voltage linear regulation versus switching regulation, which reduces large components and eliminates switching noise.
Voltage measurements have been taken, with care as lethal voltages are usually exposed; not for those not sure what they're doing.
To start, here is inside an Ikea 40W (3.3W) 450 lumen LED bulb. Regular CDN price is $1.99 for a 2-pack, which must be a loss-leader. The 60W version costs $6.99 for 2-pack. No way could they manufacture, package, and sell this bulb for $1, at any profit, even for the material cost with two PCBs.
Unlike most low-cost ac bulbs, this one uses switching topology, using two inductors, one for the switcher and other for noise filter. The 4-pin switching control chip is marked PT4558EN (Powtech), not much detail found.
Each LED package has vf around 16v which indicates 6 series LEDs. Two die are visible so each is 3 LEDs. 10 packages are wired two parallel, five pairs in series.
The black component on one line input wire appears to be a fusible resistor (10 ohms).
Dave
Majority of these use high-voltage linear regulation versus switching regulation, which reduces large components and eliminates switching noise.
Voltage measurements have been taken, with care as lethal voltages are usually exposed; not for those not sure what they're doing.
To start, here is inside an Ikea 40W (3.3W) 450 lumen LED bulb. Regular CDN price is $1.99 for a 2-pack, which must be a loss-leader. The 60W version costs $6.99 for 2-pack. No way could they manufacture, package, and sell this bulb for $1, at any profit, even for the material cost with two PCBs.
Unlike most low-cost ac bulbs, this one uses switching topology, using two inductors, one for the switcher and other for noise filter. The 4-pin switching control chip is marked PT4558EN (Powtech), not much detail found.
Each LED package has vf around 16v which indicates 6 series LEDs. Two die are visible so each is 3 LEDs. 10 packages are wired two parallel, five pairs in series.
The black component on one line input wire appears to be a fusible resistor (10 ohms).
Dave
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