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Dimmer

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sammy004

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Hi guys I was working on a dimmer here and I was kinda stuck on how to hook up the 50K pot. I did easy circuits before and I have no training in this field what I know is from the wold wide web. Now I'm kinda stuck on how a pot works, see this is the curcuit I'm working on....
**broken link removed**
and this is how I have it hooked up but it keeps the light on the whole time it does not dim can someone please tell me what I am doing wrong.
**broken link removed**
**broken link removed**
 
Do not connect a solderless breadboard to 110VAC or you'll invent fire. Bare wires = danger and possible more fire.
Solder, insulation and HV skills will keep you safe and alive.
Plus that's a logarithmic volume control, not what you need for a dimmer.
 
So what do I need for a dimmer and how to I test that circuit without a breadboard?
 
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That circuit has no earth ground and needs to be double insulated so there is no chance that a dangerous voltage can be exposed. It should never be connected to mains power while the insulated enclosure is open. After building it you should really have it checked over by a qualified electrician before plugging it in.

Bill, where do you see a log marking on the pot? I agree it's probably not up to the task (pot *or* switch) but it could be linear, no?

All in all, mains-powered circuits are not for the beginner. That thing could hurt you, kill you, or start a fire, and that picture just scares the willies out of me.


Torben
 
I am surprised that nobody else noticed that those two wires are not connected to the ends of the pot as in the diagram. Instead they are connected to the switch. That's why the circuit won't work.

Other than that, use insulated wire and solder the joints on the pot, and beware of electrocuting yourself!

Bob
 
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Bob Scott said:
I am surprised that nobody else noticed that those two wires are not connected to the ends of the pot as in the diagram. Instead they are connected to the switch. That's why the circuit won't work.

Other than that, use insulated wire and solder the joints on the pot, and beware of electrocuting yourself!

Bob

Holy cow, you're right. Never got past the initial reaction, I guess. :)


Torben
 
The POT has a switch, generally used on a volume control for off / on. It could be a linear, but my moneys on log because of the switch (which isn't in the schematic though)
 
blueroomelectronics said:
The POT has a switch, generally used on a volume control for off / on. It could be a linear, but my moneys on log because of the switch (which isn't in the schematic though)

Gotcha. Just wondered because I've got both kinds in my box.


Torben
 
sammy004 said:
So what do I need for a dimmer and how to I test that circuit without a breadboard?


you can use your breadboard! get some insulated wire! and get yourself a three pin pot, that thing you have created scares me :eek:

are you just wanting to use a pot to dim a LED?

just connect your pot in series with your LED and, of you go , done!!!
Use a 9V battery to be on the safe side and put a 350ohm resistor in series as well so you don't exceed 20mA(assuming the LED has a voltage drop of 2V)
 
Hey guys thanks for looking after me but I didn't ask for safety 101, I just wanted to know if that is the right pot or not, and are the CONNECTION on the right points not what they look like.

shaneshane1 said:
you can use your breadboard! get some insulated wire! and get yourself a three pin pot, that thing you have created scares me :eek:

are you just wanting to use a pot to dim a LED?

just connect your pot in series with your LED and, of you go , done!!!
Use a 9V battery to be on the safe side and put a 350ohm resistor in series as well so you don't exceed 20mA(assuming the LED has a voltage drop of 2V)
This is not for a LED and I'm not using any LED's.

Sorry to sound all uptight but with this project and my C++ Project I'm just going over the roof in frustration. So all I'm asking for is advice not a lesson on what electricity does!!!

Thank You
 
sammy004 said:
Hey guys thanks for looking after me but I didn't ask for safety 101, I just wanted to know if that is the right pot or not, and are the CONNECTION on the right points not what they look like.

Hold on, chill out. Nobody's telepathic here. We saw something unsafe. Like seeing someone try to clean a gun with the breach closed or stoke a fire using a full gas can.

What the connections look like gives some indication of how they will behave when you turn it on. The notes aren't aesthetic, they're practical. Just twisting leads like that is something that I've found, through painful experience, makes circuits behave oddly.

This is not for a LED and I'm not using any LED's.

Sorry to sound all uptight but with this project and my C++ Project I'm just going over the roof in frustration. So all I'm asking for is advice not a lesson on what electricity does!!!

Thank You

Maybe you should explain what you're trying to do, not how. Could be there's a simpler (and safer) option. Nobody here wants to give advice and then read about it the next morning in the paper.


Torben
 
hi,
This is how the pot is configured,

Please do NOT use a breadboard for developing mains powered circuits.:eek:

Also be aware that some pots are made with metallic shafts, I know they are supposed to electrically safe, but I would not use that type.

Does this explain it OK.?
 
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Can you post a picture of the complete circuit?


Torben
 
Torben said:
Can you post a picture of the complete circuit?


Torben

Morning Torben,
The OP did post the circuit in his 1st post, its a bog standard mains lamp dimmer.

Regards:)
 
ericgibbs said:
Morning Torben,
The OP did post the circuit in his 1st post, its a bog standard mains lamp dimmer.

Regards:)

Morning!

Sorry, I meant the constructed circuit on the breadboard. :)


Torben
 
Torben said:
Morning!

Sorry, I meant the constructed circuit on the breadboard. :)


Torben

You probably cant see it for the 'smoke'....:rolleyes:
 
sammy004 said:
Hey guys thanks for looking after me but I didn't ask for safety 101, I just wanted to know if that is the right pot or not, and are the CONNECTION on the right points not what they look like.

It would be irresponsible and negligent to not inform someone that their circuit was potentially dangerous and could kill them and or cause property damage. It was obvious from the photo that you're not an electrician.
Working with low voltage devices (<10V, <1A) is generally considered safe, but working with 110VAC or higher often requires certification or at the least an apprenticeship.

Some folks seem to think because they saw something on the web or in these forums it's all good. Take a look at the 220V 555 burglar alarm thread, the OP blamed the forum members for not informing him it wouldn't work; who in their right mind would build it in the first place. Every one here said it was a bad design, guess we should have added a poor one too.

What course combines C++ with mains electrical anyway? If it's not a course then sign up for some formal night school on electricity if it's a hobby. Else stay away from your power lines.

Are you using an isolation transformer?
 
blueroomelectronics said:
It would be irresponsible and negligent to not inform someone that their circuit was potentially dangerous and could kill them and or cause property damage. It was obvious from the photo that you're not an electrician.
Working with low voltage devices (<10V, <1A) is generally considered safe, but working with 110VAC or higher often requires certification or at the least an apprenticeship.
Well actually Mr.Blueroom I have been doing house wiring for the past 10 years so I know what it is like and how it feels like to have a little bit of energy hit you (happened twice in 10 years). Had this been a 220-240 volt circuit then s**** it I would never come close to it.

blueroomelectronics said:
Some folks seem to think because they saw something on the web or in these forums it's all good. Take a look at the 220V 555 burglar alarm thread, the OP blamed the forum members for not informing him it wouldn't work; who in their right mind would build it in the first place. Everyone here said it was a bad design, guess we should have added a poor one too.
Why didn't you?

blueroomelectronics said:
What course combines C++ with mains electrical anyway? If it's not a course then sign up for some formal night school on electricity if it's a hobby. Else stay away from your power lines.?
And who says I'm combining C++ with mains electrical? This project is on a totally different side of the area, and C++ is a totally different item I just completed my Computer science degree and spending 5 years in school...I think I should know what is combined in C++

blueroomelectronics said:
Are you using an isolation transformer?
Yes I am should I be?

If I missunderstood anybody I apologize.
Thank you
 
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sammy004 said:
What Smoke???

Hi Sammy,
Chill, its just a little humour, no offence intended.:)

On that pot, one of the end terminals has to be connected to the centre terminal [wiper].

The end you choose to connect will determine which way the pot dims the light, CW or CCW,...OK.

Do you follow,?
 
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