Tube Mods : Very Noob Question

[Mohamed]

And I suppose if I have to ask this question I probably shouldn't be in this section I have done minor "educational" type electronic projects back in the day so I do have some background and maybe I'm just a bit rusty. Most of those were in physics with parallel and serial circuits. We did a few breadboards with minimal soldering. Anyway I think I have the basics down I'm just confused by one thing.

I can visualize how this would work in a diagram.


Symbol on far left is the battery with positive terminal at the top and negative terminal at the bottom. Bulb looking thing on far right is our resistor/attomizer. Top part is a switch that basically determines if the circuit is closed and working or open and thus in the "off" state.

I can wrap my brain around that fairly easily...but I got to thinking about my vamo and other tube mods that I have seen or even flashlights for that matter. I always see a spring at the bottom but I never see a wire connected back to the spring or negative terminal.

Is the entire stainless steel / copper / conductive tubing acting as the negative terminal at this point? Is the negative side of the atty/light bulb just connected to the inside of the conductive tubing and the electricity flows through the conductive tubing back to the spring which is connected to the negative terminal of the battery? That's about the only way I can visualize the circuit every being closed when no visible wire is touching the negative terminal of the battery. I assume at the top of these there is just a short wire that is soldered onto the inside of the conductive tubing to close the circuit?

If what I said above is true wouldn't your hand and body also be effectively acting as a resistor in the closed circuit? I realize it's such a small voltage and current and not able to do any harm but by touching it are you effectively part of the circuit as well?

Diagram anyone if I'm trying to make this overly complicated? I think my college professor is probably passed on at this point and would be disappointed in my memory of the subject.

 

[shellac]

You've pretty much got it. No wires in a mechanical, though, and typically the spring isn't part of the circuit in a mech. It's typically a solid, insulated pin making the positive contact ay the top. The bottom button makes contact with the battery negative and the tube through the switch body.

Holding the uninsulated body doesn't add resistance since the electricity still flows via
the path of least resistance.

 

[Mohamed]

You've pretty much got it. No wires in a mechanical, though, and typically the spring isn't part of the circuit in a mech. It's typically a solid, insulated pin making the positive contact ay the top. The bottom button makes contact with the battery negative and the tube through the switch body.

Holding the uninsulated body doesn't add resistance since the electricity still flows via
the path of least resistance.

Is the entire stainless steel / copper / conductive tubing acting as the negative terminal at this point? Is the negative side of the atty/light bulb just connected to the inside of the conductive tubing and the electricity flows through the conductive tubing back to the spring which is connected to the negative terminal of the battery?

Is that part correct? I guess I got to thinking about this last night...can I just view the negative terminal as being grounded and the negative side of the atty connected to the inside of the conductive tube as being grounded? Similar to diagram below?



I think I found that on same website I found the original image although I was doing a google image search for flashlight circuit diagram? I guess I'm having a hard time wrapping my mind around the fact that no wires are directly connected back to the negative terminal of the battery...but your comment of electricity flows via the path of least resistance kind of makes sense with the grounding diagram. I guess I'm having a hard time relating to what I was taught that the circuit needs to be closed in order for it to work. If it is open anywhere electricity won't flow...at least that's what I remember.

 

[BJ43]

I was taught that the circuit needs to be closed in order for it to work. If it is open anywhere electricity won't flow...at least that's what I remember.

If it is a metal tube or box that will conduct electricity it becomes a common ground and you have a closed circuit when you close the switch. Like in your car, the battery negative is connected to the chassis and body of the car and becomes a common ground.

 

[asdaq]

The only way your hand would conduct the current were if the material used for the body were less conductive than your hand. For example, a bottom firing copper mod with copper end caps on a plastic tube and you are pretty sweaty*. For once the voltage sag would be a good thing.

*Don't build this please.

 

[Mohamed]

*Don't build this please.

I don't plan on building anything at the moment. Was just trying to refresh my circuitry knowledge. I just wish I had a clearer explanation of why wire wasn't required to go back to the negative terminal of the battery.

 

[liveformoment]

The battery vents. The circuit goes to the coil.

 

[patrao_n]

Wire isn't necessary because of the metal tube. The body will ground to the atomizer. So since the middle pin is insulated it doesn't matter. It completes the circuit when you hit the button.

Sent from my SM-N900T using Tapatalk

 

[Train2]

You had it right in your first guess - the tube itself is closing the negative half of the loop.
Your hand isn't involved because the tube is more conductive than you are.
There ARE a couple mods with a plastic tube - they require a wire to close the circuit.

 

[sawlight]

As said before, it's like a car, the entire metal structure is negatively energized. Remember, this is DC, not AC! Any metal point on a car is a ground, the starter doesn't have a ground wire going to it, just a positive wire. The positive wire is energized, the ground is made through the body of the starter, to the engine block, to the frame, to the battery completing the circuit.
Same with a flashlight or APV, the metal part is always negatively energized and the positive is switched completing the circuit. Depending on the metal used is how much of a voltage drop you get. The less conductive the metal, the more drop, the more conductive, the less drop.
NO, you will not get energized, same as your car getting hit with lightning, the shell creates a Faraday cage insulating you unless there is a direct short somewhere. Even then the most you should experience is the tube getting warm or hot.

 

[Mohamed]

You had it right in your first guess - the tube itself is closing the negative half of the loop.
Your hand isn't involved because the tube is more conductive than you are.
There ARE a couple mods with a plastic tube - they require a wire to close the circuit.

That's kind of what I was figuring. I thought it had to be because of the conductivity of the tube. I have seen plastic flashlights that don't seem to have any wires connected back...although maybe the inside is made of a thin metal. I'll have to see if I can't find the flashlight I was thinking about.

Since we moved about 5 years ago I still have about 4 boxes sitting in basement or garage. Wife says if you haven't used it in 2 years that it's a rule that you throw it out. I don't like throwing anything out even if hasn't been used

 

[Mohamed]

And thanks all for the refresher course

 

[asdaq]

You had it right in your first guess - the tube itself is closing the negative half of the loop.
Your hand isn't involved because the tube is more conductive than you are.
There ARE a couple mods with a plastic tube - they require a wire to close the circuit.

The example I had in mind has no wire inside and requires a wet hand to complete the circuit. Again, strictly for illustrative purposes.