What are a light switch and a dimmer switch?

You can turn On any lights be it at home, in a machine, or vehicle by using the ‘light switch’ but sometimes for some reasons you don’t want the full beam of light therefore, you use the dimmer switch so you can go from high beam to low beam and vice versa. Sometimes the arrangement is three positions, that is, high, low and off. However some applications demand smooth control of light intensity between low and high. In this case intensity is continuously variable using any of different variations and technique used for dimmer. There are different Variations of Dimmer Switch including:

  1. Programmable dimming control via ARDUINO etc.
  2. Some phase shift control by TRIAC
  3. PWM power control
  4. Simple transistor control
  5. Steps Transformer Control
  6. Potentiometer/Rheostat

Where is a dimmer switch useful?

A dimmer will work with incandescent and LED lights, and DC motors; also heating elements such as power control of heating devices like heating element in Water Bath, Incubator, and hot air oven/sterilizers. However there are design variations and complexity but the type of simple control is not smooth but it does work. One good thing about this is that it is durable and sustainable. Precision may not be taken seriously but it is accurate.

Dimmer Switch is used in:

  • Light intensity control for ophthalmic equipment like microscope: ophthalmoscope, slit lamp, bipolar coagulating diathermy etc.
  • Light intensity control for homes and apartment
  • Could be adapted to speed control of small electric motors

How do I make a simple Dimmer switch?

The simplest dimmer switch is a variable resistor also commonly called rheostat. You achieve control by varying the resistance between the light and the power supplies. When a variable resistor is used in a circuit to vary the brightness of a light bulb, you make the resistance greater when you want a dimmer light setting and you make the resistance smaller when you want a brighter light setting. Resistance is increased by increasing the length of the path of resistive material through which the electrons have to flow, and is decreased by decreasing the length of the path. .

Resistance is calculated in an electrical circuit, like the one below, through the use of Ohm’s law, and is measured in the units of ohms.


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