How about the wattage of the hidden LED lamp belt?
With the power to the lamp, light stability, and then with a clip on ammeter multimeter to measure current and voltage in the circuit, lamp with P total =U*I not even out of it!
The LED has different chips that cause different currents. For example: there are 0.011A; 0.015A; 0.028A and so on, it should be said that different batches of LED chip will have different values of the current, so each batch should be measured by instruments. In general, the 30 light / meter band will use a larger current of LED. For example: 0.028A, calculate the power per meter (30 / 3: lamp lamp group) * (12V * 0.028A) =3.36W; and 60 meters of lamp / lamp with LED will use less current to produce, for example: 0.011A, calculate the power per meter (60 / 3: lamp lamp group (x) 12V * 0.011A =2.64W). The use of resistance but also according to your current input voltage and depending on LED, because LED rated current is 20MA, but the actual application generally do not use 20MA, usually 15--18MA! To the series resistance, by Ohm's law can be counted by U=IR.
1. Power calculation formula: P=UI.2, with the power to the lamp, light stability, and then with a clip on ammeter multimeter to measure current and voltage in the circuit, lamp with P =U*I.
Then you have to see what you choose. There is no standard, DC12V and AC220V are different.
