Capacitive Proximity Sensors

Capacitive proximity sensors are non-contact sensors that can detect targets through changes in capacitance. They differ slightly to proximity sensors, which simply detect the absence or presence of an object.

In other words, when there's a change in capacitance, the sensor is triggered - and from this, measurements of the unseen target object can be determined. Capacitive proximity sensors come in shielded or unshielded housings to be flush-mounted (embedded) or non-flush-mounted (non-embedded) in metal.

Browse our capacitive proximity sensor range online and place your order with us today. Need help finding a specific model? Use our smart filtering system to find the device you need. We stock reputable brands such as SICK, IFM, and Pepper+Fuchs. Be sure to get in touch with our friendly team of experts if you have any queries.

What are capacitive proximity sensors?

Using non-contact means, capacitive proximity sensors can be used to sense metallic and non-metallic material by detecting a change in capacitance.

A capacitive proximity sensor is compiled of two metal plates separated by an insulator called a dielectric. The entire component is designed to detect a target. A sufficient target has a dielectric constant larger than air. The dielectric constant is also known as an electrostatic field which is generated by an oscillator circuit.

Oscillation begins when this electrostatic field is disturbed by a target. When this happens, the trigger, otherwise known as the detector, can monitor the oscillator's output. The output circuit switches on once the change in the field reaches a certain level. Until the target is removed, this output circuit stays active. In other words, the presence of a target or object triggers the output circuit.

Capacitive sensors require the target to be relatively close, and the sensors we supply have a maximum range of 40mm. The sensing distance is greater for larger or denser targets. Ungrounded conductive material can be sensed from further away as it creates more disturbance on the electrostatic field. However, grounded conductive material has the longest sensing distance because it creates even more disturbance on the electrostatic field. To deal with these variations, many capacitive proximity sensors have sensitivity adjustment features.

A capacitive proximity switch is different to a capacity proximity sensor, as switches rely on physical contact. They open and close an electrical current once contacting a target.

What is capacitance?

Capacitance is a measure of a component's ability to collect and store electrical charge, or energy. Larger capacitance means more charge can be stored. Capacitive distance sensing can determine certain features of a material, such how far away it is and the size of an object.

How are capacitive proximity sensors used?

Capacitive proximity sensors are used for non-contact detection. You can determine where a target object is positioned as well as its proximity. This can come in handy when assessing whether something has been displaced. They can be used in industry to identify what is behind a hidden surface, for example, as well as to detect solid materials or liquids.

Capacitive proximity sensors have several applications:

• Detection
• Inspection
• Counting
• Position

Industries that use capacitive proximity sensors

The versatility of capacity proximity sensors means they can be used in a range of industries or settings. If there is a need to detect an unknown substance behind a hidden surface, capacitive proximity sensors can play a role. Here are some examples of industries that use these them:

• Manufacturing
• Food processing
• Automotive and transport
• Printing
• Agriculture
• Waste and recycling
• Energy

Examples of capacitive proximity sensors in action across these industries include monitoring toner levels in the printing industry and identifying different materials in food processing.

What are the different types of capacitive proximity sensors?

When looking for a capacitive proximity sensor, you'll want to consider a few things.

Make sure the sensing range is sufficient (the sensors we supply have a range from 5mm up to 40mm). You will also want to consider whether your capacitive proximity detector is durable and able to cope with disturbances. For example, you may want to invest in a high temperature-resistant capacitive proximity sensor depending on the type of setting you plan to use it in.

Small capacitive proximity sensors

Miniature capacitive proximity sensors allow you to get into small spaces to detect the presence of materials. You can choose from wafer and cylindrical designs to suit the space in question.

High temperature capacitive proximity sensors

Some capacitive proximity sensors are designed to resist extreme heat. This is ideal if you need it to operate in spaces with high temperatures or work with hot materials. An industrial application of high temperature capacitive proximity sensors would be to detect hot wax when used in car manufacturing.

NPN and PNP capacitive proximity sensors

You can get PNP and NPN capacitive proximity sensors. PNP sensors, otherwise known as 'sourcing sensors', create a high output when a target enters the electrostatic field. Meanwhile, NPN capacitive proximity sensors create a low output when a target enters this detecting range. These are also known as 'sinking' sensors.

Why buy a capacitive proximity senor from RS?

You might need a miniature capacitive proximity sensor or perhaps a high temperature capacitive proximity sensor for detection purposes in an upcoming project - either way, you can rest assured that RS has an extensive selection to choose from.

We're an ECIA, CTPAT, and NAED-certified electrical supplier with a trusted network of suppliers and manufacturers. This means you can get capacitive proximity sensors from leading names like Carlo Gavazzi, Inc., Panasonic Industrial Automation, and TURCK.

Our same-day dispatch on selected products means you won't be kept waiting. Your order will be processed and packaged at our Texas-based distribution center. If you aren't satisfied with your order, our easy returns policy keeps things simple, reducing any hassle.

Do you have any questions about our range of capacitive proximity sensors? Get in touch with our friendly experts. They will be more than happy to help.