I bought some of this mains voltage (240v) LED tape to take a look at. It's very similar to the mains voltage LED tube-light used in Christmas lighting in that it uses a common rectifier to convert the mains to unsmoothed DC which is connected to two bus wires that run the length of the tube/strip.
Sections of LEDs and resistors wired in series are then tapped off that bus so the tube/strip lights along its full length, but can usually be cut every metre and capped.
In this case each metre has 60 LEDs in series with 22 330 ohm resistors spaced amongst the LEDs to limit the current. It's obvious that each metre of strip can be cut in half to use it on lower voltage like 120V.
Power dissipation is roughly 5W per metre and the current is about 22mA per metre section.
I thought the rectifier box was moulded onto the cable, but it's not. It's just clipped together and while that's a downside for outdoor use, the chunky rectifier and fuse inside was a pleasant surprise.
The lack of smoothing means there is a slight flicker that may be noticeable in peripheral vision and certainly cause the iPad's camera issues at the end of the video.
Sections of LEDs and resistors wired in series are then tapped off that bus so the tube/strip lights along its full length, but can usually be cut every metre and capped.
In this case each metre has 60 LEDs in series with 22 330 ohm resistors spaced amongst the LEDs to limit the current. It's obvious that each metre of strip can be cut in half to use it on lower voltage like 120V.
Power dissipation is roughly 5W per metre and the current is about 22mA per metre section.
I thought the rectifier box was moulded onto the cable, but it's not. It's just clipped together and while that's a downside for outdoor use, the chunky rectifier and fuse inside was a pleasant surprise.
The lack of smoothing means there is a slight flicker that may be noticeable in peripheral vision and certainly cause the iPad's camera issues at the end of the video.
Is there room for upgrade ? For some capacitor to smooth flickering ?
Hi Clive, do you notice with the led tapes, the series resistors burn a significant amount of power?
look at the cute little fuse. Say hi to the camera, fuse!
The 50 cm sections are probably just limits on the size of PCB material that can be manufactured. Regular 12V led tape is usually also made in sections of 50 cm, despite being sold per meter+. Single PCBs a meter long can be made, but they're extremely expensive.
I mean, a side benefit is that they can manufacture it as 110V pretty easily, with the same PCBs and just twice as many of the gaps/connections onto the busbars, but the first thing is that that's how long their PCBs get 🙂
Plasti-dip is a great water proofing tool.
Being mains voltage, what do you think would be the maximum run length for LED tape of this kind?
Well, since most LED lighting systems fail because the power supply fails, what's the harm in running the LEDs a little hot?
I spotted a dead LED. DC live ends – even more dangerous than AC.
i reckon there's enough room in that box for 4 diodes and a 400v cap soldered point to point but nothing can help with the 1m interval gap unfortunately