Sorry, but that's not how LED voltages work. The voltage drop across a LED (or any diode) is constant once it is fully conducting, the amount determined by the wavelength of light emitted. If the per-photon energy is expressed in electron-volts, that is also the voltage drop. When connected to a fixed-voltage source, a current-limiting series resistor is required. Supposing the blue LED has a 3 V drop and is driven by a 5 V supply, the voltage across the series resistor will be 2 V. Substituting a green LED with a voltage drop closer to 2 V, the current will increase by nearly 50% which might be too much. You need to check the rated current of the replacement LED and work out a suitable resistor value to go with it. Limiting the current to less than the maximum simply reduces the brightness.Unless it's already printed on the PCB, I'd suggest you first very carefully check voltage and polarity of the existing LED in-situ then match the replacement accordingly. You need to get it in the right voltage range as most LEDs will only give you their rated light output within some tenths of a volt of specified value, and obviously polarity is important.
Sorry, but that's not how LED voltages work...
Sorry, but that's not how LED voltages work. The voltage drop across a LED (or any diode) is constant once it is fully conducting, the amount determined by the wavelength of light emitted. If the per-photon energy is expressed in electron-volts, that is also the voltage drop. When connected to a fixed-voltage source, a current-limiting series resistor is required. Supposing the blue LED has a 3 V drop and is driven by a 5 V supply, the voltage across the series resistor will be 2 V. Substituting a green LED with a voltage drop closer to 2 V, the current will increase by nearly 50% which might be too much. You need to check the rated current of the replacement LED and work out a suitable resistor value to go with it. Limiting the current to less than the maximum simply reduces the brightness.
I didn't know that. What is the advantage of this approach?Some green LEDS have started to use phosphor to generate the required wavelength and have a higher voltage drop.
I didn't know that. What is the advantage of this approach?