- Joined Jun 25, 2022
Extremely sorry can't see anything written on the board, but im connecting it to my wall socket 230v ac.What is the rated input voltage of this power supply?
If you operate it with no load, then the voltage on the electrolytic capacitor will rise to the mains voltage. If you subsequently connect the LEDs across the electrolytic (although that’s where they should connect) then they will probably fail due to the current surge. Make sure that everything is discharged, connect the LEDs and only then connect to the mains.Extremely sorry can't see anything written on the board, but im connecting it to my wall socket 230v ac.
But why the LEDs aren't working in series (using transformer not the power supply). I double checked the anode cathode and they are all connected properly.
They use a cap as a resistor to down size the current. You must work like in dc with the R of the cap is 1/120*3.14*c if you use 3 led in serial you have to change the value of the cap to have the same curent with a larger voltage.View attachment 270774
4 little LED lights were connected in series using this power supply. I tested each led with a 9v step down transformer they worked perfectly, but when I'm attaching them in series none of them lighting up. Using the Power supply (image) isn't lighting up the leds either. What might be the issue?
Same capacitor will work fine with one LED and four LEDs in series. Voltage drop on the LED is far less than mains voltage, so the "orange capacitor" works as a current source. You may calculate the needed capacity for 2 volt output and for 2x4=8 volt output, it will be almost the same valueThey use a cap as a resistor to down size the current. ...... if you use 3 led in serial you have to change the value of the cap to have the same curent with a larger voltage.
What resistance do you have in series with your LED string?
What colour LEDs? White LEDs would need about 12V to drive a 4-LED string.
Is your "transformer" the old-school heavy iron type with an AC output, or is it a light-weight switch-mode type with a DC output?
The power supply shown is a capacitive voltage-dropper type and is dangerous when powered directly from the house mains, as it provides no isolation from the mains.
No such diodes, and these are the led im using..... multicolourThe power supply in your picture is a transformer less design. This will not provide any isolation from the mains supply SO BE VERY CAREFUL as the output will be at mains potential. Are you sure that you have connected the LEDs with the correct polarity ?
Is there a zener diode across the output of the power supply to limit it's output voltage ? If so it may be limiting the voltage to less than that required by the string of LEDs.
Yes there a constant multicolour light while connecting each of them to a 9v dcThey can’t be RGB because they don't have enough pins.
They could be red-green, so the polarity can’t be wrong because one polarity gives red and the other polarity gives green.
How much voltage are you measuring across them when you think that the should be illuminated.?
|Thread starter||Similar threads||Forum||Replies||Date|
|J||Need power adapter HELP theater seats aren't working||Power Electronics||4|
|D||Why aren't fibre-optics used more?||General Electronics Chat||13|
|D||These Cougar's aren't fighting ?||Off-Topic||2|
|Gift idea for kids who aren't stupid: Snap Circuits||Off-Topic||5|
|9V batteries that aren't 9V||Power Electronics||6|
by Jeff Child