i want to join three rainbow leds supply voltage is by mains adapter input 230-240v output 4v - max6Va in line for an illumination project can it be done with just resistors if so what rating do i need led fV typ. 3.8v(max 4.5v) forw current 20-40mA
A typical LED on a 12 volt circuit requires a 1000 ohm resistor. According to what you wrote your output voltage is 4 and max for your LEDs is 4.5. But to be safe you should be fine with anything between 200 and 300 ohms.
a 1000 ohm resister for a 12 v input??? wow.. overbored.. for 12 volts, go with 470 ohm
Use 390 Ohm resistors for a special project or LED configuration.
Use 470 Ohm resistors with Blue, Green, White, U.V., Aqua & Pink LEDs.
Use 560 Ohm resistors with Red, Yellow & Orange LEDs.
im not sure i understand.. u say your input is 4 volts, 6 Volt amps right?
your LED is 3.8v - 4.5 v .. then u are in the range, and wont need a resister right?
u are fine, leds dont draw the amps, they draw the voltage..
u say your Output is 4 volts, 6 Volt amps right?
typo**
the information i posted was taken from the power supply and packet the leds came in, i will lay it out as it is laid out: on the 2 items:
transformer.
model: JW - BN - A4 - 06
input:: 230-240 - 50Hz
output: 4V - Max6VA
lumitronix LEDs - rainbow LED 20dgre 5mm 3.6V
emitting color: Rainbow
luminous intensity: R 1500, G 4000, B 2000mcd
viewing angle 20?
size: 5mm
forward voltage: typ. 3.6V (max 4.5V)
forward curren :: 20 - 40 mA
what i want to happen is, to join 3 LEDs clustered together ( .'. like this) and when switched on they light and change sequence (red, green, blue). thank you for any help you can give, as it is for a project i want to do for a DISABLED Charity.
So what u are saying is that these are the LED's u are using? it is one LED that changes color right?
https://www.leds.de/product_info.php?language=en&info=p53_Rainbow-LED-20--5mm-3-
8V.htmlthis store is very expensive for LED lights, i can see why u want to make sure u are doing it right.
if the LED's change color themselfs (2 terminals, 1 positive, 1 negative) then i can help you.
these will work with out resistors with that type of transformer (becuase its within the voltage range)
BUT
The site i normally buy LEDS from say theres are 3.3v - 3.6 volts and 20mA ..
you can add resistors if u wish. i dont think it will hurt if u dont add them, but u can be safe and add them anyway.
the Resister size you will need is a 20 ohm Resistor.
4 volts input
LED is 3.6 volts
--------- =
.4 volts differnt
LED is .02 amps
.4/.02 = 20 ohm
anything between
10 - 20 ohms resistor will keep you safe.
10 ohms becuase input current could be .04
.4 volts / .04 amps = 10 ohms
this is if your Voltage is 4 volts. you should be fine then
site i buy all my LEDS
https://www.lck-led.com/product_info.php?cPath=2_66&products_id=150there only $3.40 for 10 LEDS .. shipping for me was never over $3 ... i bought 200 leds last month and shipping was $2.90 .. if u join them, u get $5 off your order.. but i havent used it yet (join as in u give them your name and email) there a awesome company that ships right from china