questions about wiring a vv mod and finding parts

[Nepherael]

Hi guys. I will be building a variable voltage juice fed mod with a digital voltmeter display.

Before I get into this let me state that I have small experience with electronics and soldering. I can understand a wiring diagram and once I'm told something I won't forget it but I do need it explained in depth.

I can't seem to find a digital display to tell me what voltage I'm at ( I have seen a mod on here with it)
I'm not sure what part I'm looking for to change the voltage. I thought it was different from a regulator but I can't seem to find anything but regulators on e-cig DIY websites.

And I've been all over trying to find a guide to wire something like this up (im sure if I had found that guide it would already know what all the parts are and where to get them)

And is it smart buy parts with the highest power/amp rating so they don't burn out? If not please explain.

So if anyone could help me with any of the above I would greatly appreciate it


Neph

 

[o4_srt]

you're looking for an adjustable regulator, preferably switching (they are more efficient) with Vin of 6 volts min, Vout of 3-6 volts, and Iout of at least 2 amps.

Additionally, you will need a potentiometer, or some type of variable resistance device, to adjust voltage. I'll direct you to the Evercool Variable Voltage mod posted a few posts down in the battery mods section. The regulator is available for free if you request an engineering sample straight from TI.

for the voltmeter, do a google search for digital panel meters, select one that has a range suitable for your mod, and that is capable of being powered by the input (not requiring an independent power supply) and you should be good to go

 

[Nepherael]

Thank you very much. That was very helpful. Now if anyone has any more suggestions on all that or if anyone knows a good guide/video for putting it all together.
Also why would I need an adjustable regulator if I'm going to use a potentiometer? Does the regulator being adjustable just allow the potentiometer to work?

 

[o4_srt]

Thank you very much. That was very helpful. Now if anyone has any more suggestions on all that or if anyone knows a good guide/video for putting it all together.
Also why would I need an adjustable regulator if I'm going to use a potentiometer? Does the regulator being adjustable just allow the potentiometer to work?

that is correct. A standard 5 volt regulator has 3 pins: Vin, Vout, and Ground. An adjustable has those three, and also has a Vadj, which you use in conjunction with a voltage divider (which is just 2 resistors, in this case, one fixed value, the other is the potentiometer). The resistance set in the voltage divider determines your Vout.

 

[o4_srt]

that is correct. A standard 5 volt regulator has 3 pins: Vin, Vout, and Ground. There is no easy way to adjust the output without affecting the current. By using a potentiometer on the output of a standard regulator, you will successfully adjust the voltage, but it will also lower current, as the resistor (or pot) will dissipate some of the electrical energy as heat.

An adjustable has a Vadj pin, which you use in conjunction with a voltage divider (which is just 2 resistors, in this case, one fixed value, the other is the potentiometer). The resistance set in the voltage divider determines your Vout.

attached is a VERY crude schematic of a basic regulator in use. To make it adjustable, R2 is replaced with the potentiometer. Values depend on the regulator being used.