5v troubleshooting

[Phonernomicon]

Built a 5v box last night. It vapes great! The problem I have is with the led. I need one for the master on off switch so indont leave it on all the time... Which I did with my previous 5v box.
The led in have worked great at first, but a couple longer vapes and it stopped working. Thennit would randomly come on, and now it does nothing. It doesn't look burnt but it just sits there, still vapes fine though. Maybe inhave a the wrong resistor? I'm using a 4 pin voltage reg from madvapes.
Pin 1- Master +>470ohm resistor>led>swich>vreg
Pin 2- Vreg>atty pos
Pin 3- Vreg>atty neg>led neg>470 resistor
Pin 4- Vreg>switch>470 resistor

any ideas why the led isn't working?

 

[Rocketman]

Looking over your wiring it looks a little different than the diagram on madvapes site.
Your vape switch is in the regulator to output path. That works, just different.
Your LED resistor connects to the regulator output and one lead of your LED is to the ground lead. I can't make out the other end of the LED or LED resistor.
The LED and resistor need to be connected in series (like they were a single component) across the voltage you want to monitor. The midpoint should not be connected to anything else. The 470 ohm resistor and LED connected across the 5 volts would give 6ma with a red LED, and 4ma with a blue LED, which is fine.

Rocket

 

[Phonernomicon]

Ah I get what i did with the switch. I should have put it on the 5v output instead of the input. So instead of turning on the atty, I'm turning on the whole circuit.
I have. 470ohm resistor in series before the led. I have it set battery plus to 470ohm resistor leg, second resitor leg to led positive. Then the led ground is on the ground pin. So I'm sennong the led 7.4v I'm guessing I need a different resistor, and next time I'll put it in the 5v output before the switch. Weird thing is it doesn't look burned out, and it did work for a bit.

 

[Rocketman]

THe main power switch should shut down everything. The vape switch CAN be put in the following places and work:
1)Input pin of regulator, turning off regulator which turns off atty,
2)output pin of regulator letting regulator run and switching the atty,
3)Ground lead from atty, stops current flow through atty,

The addition of a small electrolytic capacitor, even 1 uf would help the life of the regulator. But since the load is low resistance (1.5 to 4 ohms is low to this device) eliminating the capacitor ain't all that bad.

If you look at the chip in the LED using the dome as a magnifying glass you may notice the center looks brown. Compare it to other LED and sometimes you can see a darker color. The chip in there is small.

The idea behind the resistor for the LED is the LED needs about 1.9 to 2.0 volts to turn on. Once it turns on 2.1 volts makes it bright, 2.2 volts makes it very bright 2.3 volts burns it out. The resistor drops voltage. The more current the LED tries to draw the more voltage is dropped across the resistor. Eventually higher voltage will still pass too much current and burn out the LED. 10 to 20 ma is a lot for most of these. If they are connected across a voltage source without a resistor they will try to conduct all that is available. Poof.

R

 

[Phonernomicon]

Checked on my resistor and it fell off the board.. So my guess is it wasn't even doing anything. Hence the burnout so quick. I'll just have to rework the board again when I get off work. I'll move the led to the output and see if that helps. Thanks

 

[Rocketman]

Best place for power led is input to regulator before vape switch, will indicate power to regulator.
Anode of LED to Plus, Cathode of LED to resistor (don't use a contact used by anything else), resistor to negative (regulator Ground)

R

 

[Phonernomicon]

Okay so how I had it, but with an actual working resistor. This all makes a little more sense of why it's wired this way.