My question is basically this:
How can a make a DC circuit with adjustable resistance?
I was going to use a potentiometer, until I found out that potentiometers start at about 1kohm, and my circuit needs adjustment between 0 and about 5 ohm. I found some pots that low on some specialty electronics sites, but they cost like 100 bucks. Which leads me to a follow up question:
Shouldn't it be cheaper to build a low resistance pot than a high resistance one?
For those of you wondering how anyone can be so ignorant and why I am even asking, here is some background, don't feel obliged to read any of this:
This is not homework per se, but I believe it is roughly on the same level of difficulty of highschool homework and I did't want to bother people in serious discussions with my noob question.
I smoke an e-cigarette and I got sick of recharging batteries all the time, so I wired up a simple wall plug adapter. I got a 5v 1a cellphone charger, and connected the leads through a button to the vaporiser terminals. This worked quite well, an e-cig circuit is just simple element so my very limited knowledge of electronics was enough. The issue is that the power output of the adapter is a bit high, the standard for these devices is usually around 4 volts at about 500ma (at least that was what someone on the forum measured). This means it burns too hot sometimes. As the element ages it gets worse so this extra power is great for getting more life out of an old element, but with a new element it is just far too hot. I build my own elements so I can build some that will cope better with the higher power, but then when I am out and about and dont have a handy wall socket I have to use my batteries, and then it is too cold.
My plan was to simply install an adjuster knob, but as I said above nothing I can get from an electronics store will do the job. I researched for hours on the web, and came up with nothing. I did manage to work out the calculations for the result of adding resistance to the circuit, using this very nifty simulator. Basically if I add 5 ohms to the circuit before the element it will be pretty much unworkably cold, 2 ohms will bring it onto the same rough level as my batteries. Using a 1k pot with a 270 degree turn would mean turning the knob 1 degree would pretty much turn off the device.
I understand there is probably something very basic and obvious I am missing here but I started self teaching electronics a few hours ago so I hope it is understandable.
How can a make a DC circuit with adjustable resistance?
I was going to use a potentiometer, until I found out that potentiometers start at about 1kohm, and my circuit needs adjustment between 0 and about 5 ohm. I found some pots that low on some specialty electronics sites, but they cost like 100 bucks. Which leads me to a follow up question:
Shouldn't it be cheaper to build a low resistance pot than a high resistance one?
For those of you wondering how anyone can be so ignorant and why I am even asking, here is some background, don't feel obliged to read any of this:
This is not homework per se, but I believe it is roughly on the same level of difficulty of highschool homework and I did't want to bother people in serious discussions with my noob question.
I smoke an e-cigarette and I got sick of recharging batteries all the time, so I wired up a simple wall plug adapter. I got a 5v 1a cellphone charger, and connected the leads through a button to the vaporiser terminals. This worked quite well, an e-cig circuit is just simple element so my very limited knowledge of electronics was enough. The issue is that the power output of the adapter is a bit high, the standard for these devices is usually around 4 volts at about 500ma (at least that was what someone on the forum measured). This means it burns too hot sometimes. As the element ages it gets worse so this extra power is great for getting more life out of an old element, but with a new element it is just far too hot. I build my own elements so I can build some that will cope better with the higher power, but then when I am out and about and dont have a handy wall socket I have to use my batteries, and then it is too cold.
My plan was to simply install an adjuster knob, but as I said above nothing I can get from an electronics store will do the job. I researched for hours on the web, and came up with nothing. I did manage to work out the calculations for the result of adding resistance to the circuit, using this very nifty simulator. Basically if I add 5 ohms to the circuit before the element it will be pretty much unworkably cold, 2 ohms will bring it onto the same rough level as my batteries. Using a 1k pot with a 270 degree turn would mean turning the knob 1 degree would pretty much turn off the device.
I understand there is probably something very basic and obvious I am missing here but I started self teaching electronics a few hours ago so I hope it is understandable.