audioguru said:
You don't have LEDs, you have an IC circuit that is driving LEDs that probably have different voltages.
Exactly, thay behave more like flashing LEDs. Quite often no series resistor is required because the IC limits the current. Some flashing LEDs work from 5V others from 12V, the type I have will work from 4.5V to 16V, no current limiting resistor is required!
Let's look at the specification, because it contains some contradictions:
Emitted colour: Slow RGB change.
How does this work?
I assume it slowly change from one colour to the next by blending one colour into another. What would be a simple way of doing this? You could use PWM to vary the duty cycle of each chip or just vary the current in a linear fashion.
Forward voltage: <3.6V
I assume this is because it varies depending on the colour. I suppose this could indicate you need a variable resistor.
Reverse Current (?A): 30
What does ?A mean? Does it mean they're not sure and 30 what, amps? The normal acceptable reverse current for an LED is normally microamps or even nannoamps, never miliamps or amps!
Maximum power dissipation: 80mw
Is that continious or instantanious. I've noticed they've used a lower case w for Watts, is this a mistake? In electrical enginneering lowercase units mean instantanious imits whilst upercase is continious.
Maximum continious foward current: 30mA
Maximum continious forward current: 75mA
Either these forward current specs are bs or the power dissipation is. 30mA*3.6V = 108mW and 70mA*3.6=252mW, what a load of utter rubbish!
Quantity : 100 and Free Resistors (Work for 12v)
What does work for 12v mean? Note the lower case v again, so does it mean they will run from 12V for short periods?
Approximately 5 second routine with colour merges and transitions.
I suppose this partly answers the first question regarding the emitted colour.
My conclusion
This specification is total crap. I wouldn't buy this rubbish as they obviously don't know what they're bloody talking about!