Given the above diagram, would it be possible to use my 60W power brick and a single LDD? How would it be wired?
It sounds like what you are saying is that each resistor would be replaced with a LDD, which would not be cost effective. Either I would need a higher Voltage supply, or multiple LDDs. (?)
power supply to driver ..driver out to LED's.
Voltage of the power supply determines # of diodes you can drive.. Add V(f) up..
Also note LDD's require a voltage differential of 2-3V...
In other words if you have a 12V power supply and run LDD's you effectively only can output 10V..
I really don't recommend under 24V ps for Ldd's that is cost ineffective.. 24-2= 22
22/3.7 = 5 and possibly 6 (depends on the diodes and drive current) in series is more cost effective..
What would be the effect of just powering that circuit with the 60W brick? It is rated at 12V (I would need to check actual voltage), but I suspect V drops very significantly as current draw rises, so as I add more LEDs, each one would have less intensity. I don't want that!
Alternatively, I could convert an old 400W computer power supply and power that circuit directly.
This is a budget build (for now). I could geek out (and may later), but I just want a basic low/medium light setup for a low tech 50g.
BTW, the resistors in that diagram, what power rating would they need?
resistors would need to be rated at 1W or better..All data is listed..
Calculator seems to assume 2x actual or better so 2W is minimum.
computer power supply could probably run 30 3w diodes
At say 500mA you would have an array of 3 in series x 10 rows.
Each row terminated w/ a 1W resistor @ 1.8Ohms..
all are estimates
and you need to be aware that you can't mix V(f)'s. All diodes should have roughly the same forward voltage..
so generally no red diodes allowed ..
though if you wanted some red you could use "full spectrum" 3w diodes which are really blue w/ heavy red emitting phosphors added.. Overall color is magenta..