Riddle me this...

[MidnighToker]

OK, I have a box mod running 2 14500 in series with a 2W 2ohm resistor. The tactile switch is sitting inline between the resistor and the 801 connector (from nerf). Got everything setup with no problem (as I've done a half dozen times before) and I get 7.8ish volts at the connector. Now the weird parts...I get a voltage reading whether or not the tactile is pressed. Even stranger is that I can NOT get an atty to fire in any way...switch pressed or not.

 

[dedmonwakin]

Sounds like a bad switch. Tac switches are junk and only tolerate 50 miliamperes. You'd be better off with a switch of a current rating of 3amp. Even the 1a mini switches at the ratshack produce better results than tact switches.

A bad switch can still pass voltage, but can most definitely restrict current. Current is probably more important than the amount of voltage being supplied to the atty. For example: 3.7v at .5 amps will produce vapor but mediocre heat. 3.7v at 1-1.5amps will produce great vapor and great heat. The higher the current, the higher effects of resistance will be with in the nichrome coil. The end result will be quick and intense heat.

Check your current reading with your meter. My bet is your getting less than .2 amp to absolutely none.

 

[MidnighToker]

Sounds like the right call dedmon. Haven't had a chance to test the current on that one, but just had another boxmod's switch die after 10 minutes.

I thought I'd be good getting tacts from a better source than RatShack (Mouser), but guess not. So what switch am I looking for? Just any momentary rated at 3a? (or at least 1a)

 

[Kewtsquirrel]

Midnight-

That's not enough wattage on that resistor, that thing is going to get insanely hot and eventually burn up. Also, your readings are going to be way off unless you are checking your everything with the atomizer connected and working.

Right now you've got an 8.4v source, with a 2 ohm resistor and a 3.6ohm resistor (the atomizer).

That means you've got 1.5A total running through your circuit (I=Vt/Rt), and you're running 3v through your 2ohm resistor, and 5.4v through your atomizer. The 2 watt resistor, with 3v/1.5A running through it, is pulling 4.5w. If you push the button without an atomizer attached, it's running 4.2A at 8.4v, or 35 watts. On a 2 watt resistor.

Try using a voltage regulator instead of resistors, you'll run into a lot less issues. At the very least, your resistor is probably screwed right now, is it still ohming out to 2 ohms?

 

[MidnighToker]

I'll have to check the resistor. I just ordered some sample v-regs this afternoon.

 

[cybervex]

You can use the tactile switch if you throw a mosfet into the mix.