# LED in series and parallel

If i have a LED which drops 3V, and 30mA through each LED and i need 8 LED in series.. does it mean that i need a total of 24V and 30mA from power supply or less?
And if i use the same circuit in parallel, does it mean i will use 3V but much more current like 0.24A?? or least current?

psparky
Gold Member
For your series circuit, I believe you would need at least 24 volts at 30 ma.

That's 720 mwatts from your source.

For parallel, 3 volts will work with 240 ma coming from source, yet each branch will get it's 30ma.

That's also 720 mwatts from your source.

1 person
mfb
Mentor
If i have a LED which drops 3V, and 30mA through each LED and i need 8 LED in series.. does it mean that i need a total of 24V and 30mA from power supply or less?
Why less? You'll need 24V and 30mA. It is safer to use a voltage a bit above 24V together with a suitable resistor in series.

And if i use the same circuit in parallel, does it mean i will use 3V but much more current like 0.24A?? or least current?
8*30mA of course. The same advice: use a resistor in series.

1 person
Baluncore