Potentiometer direct to mains for lamp

In summary, the person is seeking help with building a lamp prototype that requires a potentiometer to act as a dimmer. They are unsure if this is feasible and have found a suitable potentiometer but need help choosing the right one. However, others in the conversation caution against working with mains voltage and suggest using a transformer and SCR-based dimmer circuit for safety. They also suggest using lower voltages for the project.
  • #1
freddiev
1
0
Hi guys
I'm new here and I require some help with a project I'm working on. I'm building a lamp prototype and i need to use a potentiometer to act as a dimmer. The pot needs to fit inside a 25mm ID tube, and is connected directly to the mains. First of all is this possible? I think I have found a suitable pot http://ie.farnell.com/jsp/search/browse.jsp?N=411+1000165&Ntk=gensearch_001&Ntt=MDSP&Ntx="(although I would be grateful for help in which one to choose) Sorry If this is appears to be a stupid question, but I have very little knowledge of electronics and nobody to else to ask! If its not going to work, I would be delighted to hear alternative solutions.

Best regards
freddie
 
Last edited by a moderator:
Engineering news on Phys.org
  • #2
Mains! You need to be very careful with this. Working directly with mains is an absolute no no for people with a lack of experience. Use a transformer to step down the voltage instead.

But back to your question regarding practicality. It is impractical to use a resistor network, let alone a pot to act as a dimmer. Can you imagine the amount of heat that would be dissipated across the resistor network when connected to mains!
A feasible dimmer would make use of phase differences to vary the power across the lamp. See my reply here (post #6):
https://www.physicsforums.com/showthread.php?p=1351969
 
  • #3
I echo ranger's cautions about working with the AC mains. Please work with low-voltage projects until you learn a fair amount about electrical safety (both how to work safely with AC mains in your projects, and how to build your projects in compliance with safety regulations, like those of Underwriters Laboratories here in the US).

And as ranger says, you don't control the dimming of an incandescent lamp with a potentiomenter. You control it with a pulse-width controlled triac or pair of SCRs. That's how existing dimmers work for incandescent lamps. Dimming flourescent lamps is even more complicated.

So a good project for you would be to use a UL-approved transformer to step the AC mains down to 12VAC, and build an SCR-based dimmer circuit for a 12V lamp. That will get you lots of knowledge and experience with a real dimmer circuit, without the exposure to the shock and fire hazards associated with building an AC mains-based circuit. Sound like a plan?

http://en.wikipedia.org/wiki/Dimmer
 
  • #4
No No No !

DONT DO IT ! don't in heavens name connect such a potentiometers into a mains voltage ! they will burn with a bright light and you may get killed.

What kind of bulbs you are using? Most of the lamps work with very low voltages say under 24V, most halogens with 12V, leds even with under 3Volts.
Those are safe voltages to work with.
 

Related to Potentiometer direct to mains for lamp

1. What is a potentiometer direct to mains for lamp?

A potentiometer direct to mains for lamp is a type of electrical circuit that allows for the regulation of the amount of current flowing through a lamp. It uses a variable resistor called a potentiometer to adjust the voltage and control the brightness of the lamp.

2. How does a potentiometer direct to mains for lamp work?

The potentiometer is connected in series with the lamp and the mains power supply. By adjusting the resistance of the potentiometer, the voltage across the lamp can be varied, thus changing the brightness of the lamp. This is achieved by creating a voltage divider circuit, where the potentiometer acts as a variable resistor to control the voltage.

3. What are the advantages of using a potentiometer direct to mains for lamp?

One advantage is that it allows for more precise control of the lamp's brightness compared to using a standard on/off switch. It also offers energy efficiency by reducing the amount of power consumed by the lamp. Additionally, it can extend the lifespan of the lamp by reducing the stress on the filament.

4. Are there any safety concerns with using a potentiometer direct to mains for lamp?

Yes, there are safety concerns as the potentiometer is directly connected to the mains power supply. This means that there is a risk of electric shock if not handled properly. It is important to ensure that the potentiometer is properly insulated and secured to avoid any accidents.

5. Can a potentiometer direct to mains for lamp be used with any type of lamp?

Yes, a potentiometer direct to mains for lamp can be used with most types of lamps, including incandescent, LED, and fluorescent lamps. However, it is important to check the voltage and wattage ratings of the lamp and potentiometer to ensure compatibility and avoid any damage to the circuit or the lamp.

Similar threads

Troubleshooting a Current Divider Circuit for Dimmer Lights
    • Electrical Engineering
Replies
4
Views
3K
Making a safe and effective fly zapper
    • Electrical Engineering
Replies
17
Views
3K

Hot Threads

Recent Insights

Back
Top