Power 30 3mm LEDs (from battery powered string lights) with 5V 140mA wall power block?
I also have a power block (wall wart) from an old vacuum which outputs 5V DC 140Ma.
Is it possible to power the LED string with the power block, and if so, what kind or resistor should I substitute for the original? (and, for future reference, how did you arrive at your answer?)
How does supply wattage matter?
Might as well throw this in as well: what resistor would I need to power them with USB?