I've now added this as a project on my website at http://www.bigclive.com/diyled.htm
It's basically a super simple mains powered decorative LED lamp that has super simple circuitry and runs at VERY low power. Just quarter of a watt.
It uses a simple resistive dropper and discrete four diode rectifier to apply current limited DC to a series string of LEDs. The current is very low at about 1mA for 230/240V and 2mA for 110/120V. The resistors are common quarter watt ones, and two are used as a safety feature and to keep individual resistor heat dissipation low. The diodes are common 1N4007's but you could use 1N4004/5/6 or 7's depending on what you can find easily. The LEDs I used were just random ones from my junk box, and I deliberately mixed alternate warm and cold white LEDs with a scattering of other colours for variety. You can use any standard small LED with the ideal type being the Xmas light style side emitting ones. I converted standard lensed ones to side emitting by "cracking the ice" on them. (clipping off the end of the lens to leave a rough surface on the resin).
The light is mounted into a standard lamp base taking precautions to ensure the circuitry in the base is adequately insulated, and a plastic (or glass) bottle of suitable neck and body size can be glued into the base to form the globe.
It's worth mentioning that the simplicity of the circuitry and the low current means that if the lamp is plugged into a ceiling or wall light on its own the LEDs may glow dimly even when the switch is turned off. This is because capacitive coupling across the switch wires may pass the few microamps required to light the LEDs. It doesn't indicate a fault in the wiring.
It's basically a super simple mains powered decorative LED lamp that has super simple circuitry and runs at VERY low power. Just quarter of a watt.
It uses a simple resistive dropper and discrete four diode rectifier to apply current limited DC to a series string of LEDs. The current is very low at about 1mA for 230/240V and 2mA for 110/120V. The resistors are common quarter watt ones, and two are used as a safety feature and to keep individual resistor heat dissipation low. The diodes are common 1N4007's but you could use 1N4004/5/6 or 7's depending on what you can find easily. The LEDs I used were just random ones from my junk box, and I deliberately mixed alternate warm and cold white LEDs with a scattering of other colours for variety. You can use any standard small LED with the ideal type being the Xmas light style side emitting ones. I converted standard lensed ones to side emitting by "cracking the ice" on them. (clipping off the end of the lens to leave a rough surface on the resin).
The light is mounted into a standard lamp base taking precautions to ensure the circuitry in the base is adequately insulated, and a plastic (or glass) bottle of suitable neck and body size can be glued into the base to form the globe.
It's worth mentioning that the simplicity of the circuitry and the low current means that if the lamp is plugged into a ceiling or wall light on its own the LEDs may glow dimly even when the switch is turned off. This is because capacitive coupling across the switch wires may pass the few microamps required to light the LEDs. It doesn't indicate a fault in the wiring.
I believe the bayonet cap was invented as a safer alternative to ES. Safer because the cap itself isn’t used in the circuit and thus can never become live, making your finger a path to earth.
I’m only watching this for homework and I’m bored af
Using lossy components such as resistors is never my trait. I would use a small capacitor; not a microamp would ever get wasted. Now you waste a lot of energy, negating the benefit of using LEDs in the first place.
Hehe. It worked. I tried using SMD leds. I probably destroyed about 5 pieces by overheating them with the iron. But now, I have 20 in a row and they give a decent shine.
Can i use it with color changing leds?
I have 2000 resistors, 1000 leds but only 3 diodes. FUCK
Now your on it! That bridge teaching was the best I've seen. Simple, accurate, clear. Excellent. You are a teacher not a critic.
love it I'm gonna have to make one now.
Fantastic! Thank you for the video 🙂
what ruffley is the voltage coming through to the LEDs I can't check my son has put multimeter in the toilet lol
I managed to get some of the purple LED strings in poundland. I think they might look nice stuffed in a lamp, but I'd probably need to run it off a capacitive dropper, as they're not in series. Do you think that would work out?
Hi clive 🙂 a beginner question. doesn't the current limiting resistors dissipate more power? Ive read that a capacitive dropper is a better option as it dissipates a very little or no heat/power.
Can I use 1N4004 diodes instead of 4007s? (ordered the wrong ones) and can the resistors be lower value to get more out of the leds?, (I am in Australia so 240volt)
Thanks
I never thought it would ever be that simple !!
just out of curiousity whats the best way to calculate the resisters needed to drive the leds at a certian milla-amperage id love to build this on 120 ac but run 40 leds. which is 105 volts leaving 15 to 30 volts to drop depending on voltage of the evening. any help would be great.
Hi Clive, great video, I was wondering If I were to create multiple strings like this, without the bayonet fixing, would it be possible to run them all into one fixture, and if not, could you recommend a method of doing this, thanks.