LED resistor calculation

[Thetechnician]

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

[piratepaul]

How about some drawing software?

[Pauldf]

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

[remon7]

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

[Pauldf]

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

[piratepaul]

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