Alright so I am making a Thank You sign using of 40 - 50 Red LEDs. Im currently having trouble figuring out the wattage and resistance needed for the circuit. At first i thought to just use a 220 ohm resistor but because there is a voltage drop between each leds im not sure it if will work . All it will be is a 9 volt battery connected to a resistor connected to 40-50 leds in parallel. the LEDs have a forward voltage of 1.8-2 volts and each LEDs requires about 20ma of current. How exactly do i figure out the wattage and resistance needed for this? Help much appreciated.