Multi volt design?

[candre23]

I guess my question would be if the small resistors would pop if put in the circuit like that?

Yes they would, unless they were rated for at least a couple watts. A regulator really is the best way to go about doing voltage step-down. To be more specific, a PWM regulator would be best (most efficient), but linear regulators are cheap and simple.

 

[WillyB]

...

I guess my question would be if the small resistors would pop if put in the circuit like that? I call it simulated voltage, but really it is just producing a different current. Example:

For a standard 3ohm atty:
V=IR
5V = 1.67amp * 3ohms
7V = 1.67amp * ?
?ohms = 7V/1.67amp
? = 4.2ohms
4.2 - 3 = 1.2, so you need to add a 1.2ohm resistor to the 3ohm atty to get the same current with a 7V supply as if you had a 5V.

People generally talk about power and wattage, but I look at the current. Easier in my mind, at least.

I guess my question would be if the small resistors would pop if put in the circuit like that?

Well from your last 4.2Ω example @ 7V, watts would be 11.6. 28% of that is the 1.2Ω resistor for 3.3W. So wouldn't a 1.2Ω 5W resistor be the ticket here? But large resistors and just batteries seems like a rather clunky approach.

Candre23's points/examples make the most sense, as a consistent vape is what most would desire. An alternative would be to use one large battery and a TI DC booster. This would make for a safer one cell mod and a small charging circuit could also be added.

 

[invisiblewardog]

I did some digging and found resistors of all ratings... If I remember correctly I even found a 0.1ohm rated for 20 watts.

Depending on their actual size, it may or may not be clunky. The resistors I've worked with in the past were tiny (the size of a piece of rice). Put them side by side all connected at one end (atty side), and the other side all have their own lines to the switch. The only active resistor would be the one selected. Seems like it could be a small component.

 

[candre23]

Depending on their actual size, it may or may not be clunky. The resistors I've worked with in the past were tiny (the size of a piece of rice).

Power disipation is directly proportional to size. Those rice-sized resistors you used were probably rated for 1/8th of a watt. A 5W 1.2ohm resistor is more like 22x10mm.

 

[Dragon@HEC]

I am a new vaper but tried a 5v the other day and LOVED it. I wanted to get one but I am having problems coming up with the options that I want. I was looking for something with replaceable batteries (I go camping for a week or so at a time in the back country) and that I could select 3.7, 5 & 6V options depending on the hit I was looking for. Has anyone designed something like this or has an idea where to start? Thanks for the help.

The circuit that can adjust power by the volume is opened to the public though it is MOD of battery BOX type. Please refer if it is good. http://www.e-cigarette-forum.com/forum/battery-mods/78884-555-fet-pwm-power-controller-mod.html

 

[BuzzKill]

The whole issue is about controlling POWER ( Watts ) Either by voltage OR current ( V regs are lower cost AND less parts )
A PWM based circuit would be nice as well they are more efficient than a linear reg.

Adjustability is the KEY to the VAPE !