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Adding a Potentiometer

kitchwatembo

Jan 26, 2010
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I have a device which is basically a heater. There is an on off I-O switch on the back. What I would like to do is add a pot so i can control how hot it gets.

see my next post for the simplified circuit diagram.

the power terminal that plugs into the back reads "Cos 102F" (is the the phasor?)
and it reads "7A 125V"

What I don't know is, what resistance pot should I get so I can control this load?


I tried putting a 500k ohm pot i had lying around in the circuit, and it only turned it on for about 10% of the knobs total spin. also made the LED flicker.

thanks for any help you can offer
 

kitchwatembo

Jan 26, 2010
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Diagram to go with post #1

circuit.jpg
 

Resqueline

Jul 31, 2009
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I expect this heater runs on mains? Does it contain anything electronic? You say it has a LED, but could it be a neon lamp?
If no electronics/transformers then you can use a mains dimmer. Sorry, no pot will cut it.
I can't tell if the rating you refer to applies to the plug only - or the heater device. Nor if the 102F refers to a temperature or what.
 

kitchwatembo

Jan 26, 2010
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I've never used the term mains before, does this mean its just running straight from the main source? and no, nothing electric really. just a switch then the load in parallel with some leds. In the end I dont really care if the LEDs work or not.

as for a mains dimmer, is that just like a dimmer switch one would use in a house? I can't seem to find a lot of info on that.

I wasn't sure about the markings, the heater itself doesn't have any power ratings or anything so its most likely just the rating for the plug itself.
 

Resqueline

Jul 31, 2009
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Mains = main electric power distribution network = 115 / 230 V AC.
Dimmers can be had for wall mounting or for free cable (lying on the floor) connection.
You said nothing electric now, but I strongly assume you meant nothing electronic.
Well, what is this item btw.? A 'still heater?
 

kitchwatembo

Jan 26, 2010
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its a cheap vaporizer, its burning up all my tobacco without a temp control

yea electronic haha, whoops
 

Resqueline

Jul 31, 2009
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Ok, it draws quite a bit of power then, and you'll definitely need a dimmer rated for 7 Amps to control it safely. A thermostat would be ideal though, perhaps one like they use in ovens.
 

kitchwatembo

Jan 26, 2010
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well i went and got a push on/off dimmer switch, but since i've never done any home wiring, im not really familiar with a neutral wire. the new switch has a black wire for hot, then another black that goes to the load, which then goes to neutral. then a green for ground.

would there be a way I could hook this dimmer switch up in place of my switch?

thanks for all the help
 

Resqueline

Jul 31, 2009
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Yes, these dimmers are placed in series with the load (in the hot wire) just like a simple switch is. So I figure you can just replace the switch with the dimmer, unless the switch breaks both neutral & hot, in which case you'd need to connect the two neutrals together in some way. If the dimmer has an (internal) metal case then it should be grounded for safety.
 
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