Photocells are photoelectric control devices that sense light and automatically turn on lights or other devices when it becomes dark, and turn them off when it becomes light. They work by measuring the amount of light that is present in the environment and then controlling the switching of a load based on that measurement.
The 120v photocell wiring diagram is a schematic showing how a 120VAC photocell can be wired to control a light fixture or other load. This wiring diagram is especially useful for outdoor lighting applications, such as streetlights or parking lot lights, where the photocell can provide automatic control based on the ambient light levels.
Understanding Photocells
Photocells are made up of a light-sensitive semiconductor that is placed between two electrodes. When light hits the semiconductor, it creates an electrical charge that changes the resistance of the semiconductor. This change in resistance is then used to turn on or off a load, such as a light fixture.
Photocells are available in different sensitivities, with some being more sensitive to light than others. The sensitivity of a photocell is usually expressed in terms of lux or foot-candles, which are units that measure the amount of light that is present in the environment.
Types of Photocells
There are two main types of photocells that are commonly used in lighting applications: the cadmium sulfide photocell and the silicon photocell. The cadmium sulfide photocell is the more traditional type, and it is sensitive to visible light. The silicon photocell is more modern and uses a photo-diode to detect light, and it is sensitive to both visible and infrared light.
Both types of photocells have their advantages and disadvantages, and the type that is best suited for a particular application will depend on factors such as the amount of ambient light, the temperature range of the installation, and the desired level of accuracy and reliability.
Wiring a 120VAC Photocell
The 120VAC photocell wiring diagram shows how a photocell can be wired to control a load, such as a light fixture, using 120VAC power. The wiring diagram consists of several components, including the photocell, a control relay, and a load, such as a light fixture.
Components of a 120VAC Photocell Wiring Diagram
The components of a 120VAC photocell wiring diagram include:
| Component | Description |
|---|---|
| Photocell | The photoelectric control device that measures the ambient light levels. |
| Control Relay | The relay that is used to control the switching of the load based on the photocell measurement. |
| Load | The device that is controlled by the photocell and relay, such as a light fixture. |
Wiring Procedure
The wiring procedure for a 120VAC photocell is relatively simple and straightforward. The wiring diagram shows how the photocell is connected to the control relay and load using three wires: a common wire, a normally open wire, and a normally closed wire.
The common wire is connected to the neutral or ground wire of the power source, depending on the type of installation. The normally open wire is connected to one side of the control relay, while the normally closed wire is connected to the other side of the control relay.
The load is then connected to the control relay, using the normally open contact. When the ambient light levels are low, the photocell will activate and close the normally open contact, allowing power to flow to the load. When the ambient light levels are high, the photocell will deactivate and open the normally open contact, cutting off power to the load.
FAQs
What is a Photocell?
A photocell is a photoelectric control device that measures the ambient light levels in the environment and uses that measurement to control the switching of a load, such as a light fixture. Photocells are commonly used in outdoor lighting applications, such as streetlights and parking lot lights, to provide automatic control based on the amount of light that is present.
How does a Photocell Work?
Photocells work by measuring the amount of light that is present in the environment and using that measurement to control the switching of a load. They are made up of a light-sensitive semiconductor that produces an electrical charge when light hits it, which is then used to change the resistance of the semiconductor. This change in resistance is used to turn on or off a load based on the amount of ambient light.
What is a 120VAC Photocell Wiring Diagram?
A 120VAC photocell wiring diagram is a schematic showing how a 120VAC photocell can be wired to control a load, such as a light fixture, using 120VAC power. The wiring diagram shows the components of the system, including the photocell, control relay, and load, and how they are connected to one another using three wires: a common wire, a normally open wire, and a normally closed wire.
What are the Components of a 120VAC Photocell Wiring Diagram?
The components of a 120VAC photocell wiring diagram include the photocell, control relay, and load. The photocell is the photoelectric control device that measures the ambient light levels, while the control relay is used to control the switching of the load based on the photocell measurement. The load is the device that is controlled by the photocell and relay, such as a light fixture.
What is the Wiring Procedure for a 120VAC Photocell?
The wiring procedure for a 120VAC photocell is relatively simple and straightforward. The common wire is connected to the neutral or ground wire of the power source, depending on the type of installation. The normally open wire is connected to one side of the control relay, while the normally closed wire is connected to the other side of the control relay. The load is then connected to the control relay, using the normally open contact.
