How does photocell sensor work?

How does photocell sensor work?

A photocell is a resistor that changes resistance depending on the amount of light incident on it. A photocell operates on semiconductor photoconductivity: the energy of photons hitting the semiconductor frees electrons to flow, decreasing the resistance.

How do I adjust my photocell?

The Photocell sensor can be adjusted for the light level that the switch activates. This is done with the (“LUX” screw). To adjust when the switch activates, rotate the “LUX” screw between the sun and moon symbols. sun indicates the Photocell sensor will operate at sunrise.

What is the response time of photocell?

At 1 fc of illumination the response times are typically in the range of 5 msec to 100 msec. The speed of response depends on a number of factors including light level, light history, and ambient temperature.

Where should photocells be placed?

For most general applications the photocell should be mounted between 6-8 feet of the window area, central to the area illuminated by the electrical lighting that will be controlled. In all cases the photocell must be mounted so that it looks at reflected light only and not at any direct light.

What does photocell mode mean?

Devices designed for outdoor use often include a photocell function that turns the system off during the day, which conserves energy. The adjustable timers built into some sensors lets you control how long the attached lights remain active after it detects motion.

What is the dusk to dawn setting?

But what does dusk to dawn mean? As the name suggests, these outdoor lights are placed in your garden or yard and operate after the sun has set and switch off once it rises again in the morning. Hence the name dusk to dawn. These lights can be placed anywhere in and around your garden or driveway.

What direction should a photocell face?

Photocell must be mounted vertically with the domed portion facing up.

How does temperature sensor measure temperature?

They measure temperature by measuring the change in resistance of the electric current. Thermistors are available as either NTC or PTC and are often low cost. RTDs or Resistance Temperature Detectors work in a similar way to Thermistors and measure ohmic resistance to measure temperature.

Is the temperature sensor in the thermostat?

The thermostat sensor is located near the evaporator coils. These coils are inside your air conditioner unit. It also works in reverse if the air passing the sensor is lower, or at the same temperature set on your thermostat.