New sabersmith asking some (probably) basic questions
Wellp, hello there!
This will be my first build, so I have some questions:
I'll be using:
-A basic 3.7V Li-ion battery with PBC (3,6V-4,2V, Capacity 3400Mah, Output: 4,2V 600mA, Input: 110-240V, Over Charging: 4,2V, Max charge: 1.5C) or a 7.4V Battery Pack (with a 5V (7805 type 1.5A) regulator).
-A 12W Red Quad Led (LED Type:4pcs X-Lamp XP-E Chips, Voltage: 3V, LM:1200LM Max, Current: 1000mA-3.8A(3V), Red 3V voltage infact is 3.2-3.4V).
-A cheap soundboard (As far as I know, highest power most economy boards run off is 4.2v max) and it's speaker (which I'll later change for higher quality ones).
-A non-illuminated switch.
-A recharge port (and charger, duh) like this one from TCCS (http://www.thecustomsabershop.com/37...plug-P890.aspx and http://www.thecustomsabershop.com/Sw...Jack-P822.aspx).
So now the questions are:
-Would a tip42c pnp transistor be fine for this build? I can only find examples using 7.4V instead of 3.7V single batteries.
-What if I used a 7.4V Battery Pack with a 5V Regulator (7805 type 1.5A)? Would I need Another resistor from the battery to the soundboard? Same Ohm's Law? I think I should, to make it at least around 4V while I'm using the cheapo soundboard, right?
-Now about the resistors for the LED. Using Ohm's Law it gives me this:
VfBattery => 3.7V ~> 4V
Max Current => 1000mA = 1A
VfLed => 3.2V-3.4V ~> 3.4V
R = 0.6V ~> 0.5 Ohm? 1 Ohm?
P = 0.6 * (1)^2 => 0.6W ~> 1W? 0.5W?
Or:
VfBattery => 7.4V ~> 8V
+ Voltage Regulator => 5V
R = 1.6V ~> 1.5 Ohm? 2 Ohm?
P = 1.6 * (1)^2 => 1.6W ~> 2W? 1.5W?
Is this Ok for every led? And if it's right, which resistor should I choose? It doesn't seem to matter which + or - I solder, and there's only 3 of each, so it's not like every led has it's own +-. Any + and - combination lights up all 4 leds in the star.
Also, I think these LEDs might actually run at 700mA and 2.3V (2.1-2.5V), as seen in their chart (http://www.cree.com/led-components/m...ampXPE-25A.pdf) or it's page in LED-Supply (https://www.ledsupply.com/leds/cree-...power-led-star), which looks pretty much the same as the XP-E2 Red from TCCS (http://www.thecustomsabershop.com/Re...ova-P1001.aspx), so I don't even know anymore.
