that voltage regulator, can be used for, 9v 4A down to 5v 4A,
it is of low drop?
Which regulator?
Which voltage regulator?
With that much current, you probably want a switching regulator, also known as DC/DC converter.
Otherwise (9V - 5V) * 4A = 16Watts of power has to be dissipated as heat.
I use this?
but it behaves like a voltage regulator?
ie, if a 9v battery I connect the DC / DC converter., and battery
begins to discharge up to 6 volts, the output of the DC / DC converter, maintains
5v?
Not that type, it's a step-up regulator, you need a step-down regulator and one rated at a full 4 amps if your original specifications still apply?
retrolefty:
Not that type, it's a step-up regulator, you need a step-down regulator and one rated at a full 4 amps if your original specifications still apply?if original specifications still apply
? =(
The question is: Do you need 4A of 5V current? Or do you need less, even tho your 9V source is capable of supply much more (4A)?
CrossRoads:
The question is: Do you need 4A of 5V current? Or do you need less, even tho your 9V source is capable of supply much more (4A)?
yes, I need 5v 4A.
my battery is are 2: http://www.ebay.com/itm/BRC-18650-3-7V-4500mAh-Li-ion-Rechargeable-Cell-Battery-UltraFire-Red-New-2pcs-/171095669544?pt=US_Rechargeable_Batteries&hash=item27d618bb28
my leds are these: http://www.mikrocontroller.net/attachment/180459/WS2812B_preliminary.pdf
Quantity: 64 leds rgb
power leds(64 leds ): 5V 4A
this problem, I can not fix it. and I take a long time in this.
someone help me plz
You need something like this: http://www.ebay.com/itm/390839159132
Are you connecting the 2 3.7V batteriies in series to make 7.4V that you will then regulate down to 5V?
64 LEDS, if all on full at 20mA each, need 64 * 3 * .02 = 3.84A.
#2111, maybe 2110 if you bring the current down to 18mA
would be your 2 choices here
I can't open e-bay from here, so I have no comment on the item fungus showed.
CrossRoads:
I can't open e-bay from here, so I have no comment on the item fungus showed.
It says "5A DC-DC Adjustable Buck Step Down Module..."
Here's the picture:
Description sounds good. I am network limited, pretty much limited to items that are Attached to posts via Additional Options, Browse, and Attach at the bottom of this Reply box.
and this, you say?
http://www.ebay.com/itm/390839159132
[
b]5A DC-DC Adjustable Buck Step Down Module 24V/12V/5V Voltage Regulator Converter[/b]
Module features:Module Properties: non-isolated step-down module (BUCK)
Input voltage: 4-38V
Output voltage:1.25-36V continuously adjustable
Output current :0-5A (recommended for use within 4.5A)
Output power: recommended for use in below 75W, more than 50W please add heat sink.
Working temperature: -40 to +85 degrees
Operating Frequency: 180KHz
Conversion efficiency: up to 96%
Load regulation: S (I) ? 0.8%
Voltage Regulation: S (u) ? 0.8%
Short-circuit protection: Yes (the limited current is 8A)
Over-temperature protection: Yes (automatic shutdown when over-temperature)
Input reverse polarity protection: No, (if necessary, please string into the high current diode)
Installation: two 3mm screws
Wiring: Welding, V-IN is the input, V-OUT is the output
Dimensions: 54* 23*18 (mm)
Looks good.
CrossRoads:
Looks good.
Currently at $2.05, with free shipping. 
nb. I picked a seller at random. There's other sellers selling the exact same board (and other similar boards), YMMV. You can also look for a "buy it now".
$2 and free shipping? Wow. How do they make any money?
CrossRoads:
$2 and free shipping? Wow. How do they make any money?
Well, it's an auction so that might not be the final price...
I found one for $4.68 on "buy it now". Still pretty good for a 5A device (with shipping).
CrossRoads:
$2 and free shipping? Wow. How do they make any money?
I've been speculating about this for years. All I can conclude is that they get direct gov subsides or tax credits on the actual shipping fees. Free shipping seems to be the norm on the Chinese E-bay listings.
retrolefty:
I've been speculating about this for years. All I can conclude is that they get direct gov subsides or tax credits on the actual shipping fees. Free shipping seems to be the norm on the Chinese E-bay listings.
I'm pretty sure they ship packets by containerloads to the destination countries, so that's cheap. Even so...the destination country still has to take it from the ship to your door.
I'm pretty sure I can't send a package to the next town for $2 so how do they get the post office to deliver one for a few cents? They must have some sort of a deal worked out.