Electronics 2000

I have seen the series led calculator! how about parallel l.e.d resistor calculator?.

How about some drawing software?

Simples,
just find out the voltage you require over the LED bank, add up the currents of the LEDs, subtract the voltage from the supply voltage and then R=V/I.
Then I²R to find the minimum wattage of resistor.

Example:
If you have a 9v supply and 6 off 2v LEDs, each rated 20mA each then:
9v-2v = 7v
6 x 20mA = 120mA (or 0.12A)
R= 7/0.12 = 58 ohms

Min wattage = 0.12 x 0.12 x 58 = 0.83w

Sounds very interesting and helpful! Thanks for sharing Pauldf.
LED resistor calculation fact u have to use resistor color code facts. and u can use multimeter thats perfect for resistor calculation. or use online resistor calculator. its helpful for resistor calculator. there no need to use multimeter.
http://actpcb.com/pcb-calculator
http://www.ohmslawcalculator.com/led_re ... ulator.php
An LED must have a resistor connected in series to limit the current through the LED, otherwise it will burn out almost instantly.
Thanks ...if you need more inquiry feel free ask me. i will give u right solution point of a Engineers view.

Thanks
Engineer Remon

It's just as easy to crunch the numbers yourself, gives you an understanding of it too.

Right on Paul. These calculator thingies give a very narrow understanding of what is going on in the circuit, they restrict the poss options.