What is the difference between photoelectric liquid level sensor and capacitive liquid level sensor in liquid level measurement?

What electronic components can be used for water level detection and water level control in production and daily life? A water level sensor can be used for detection. There are several types of water level sensors, including photoelectric, separate, capacitive, weighing, etc. Each type has its own characteristics and advantages. So what I want to introduce today is the comparison between photoelectric liquid level sensor and capacitive liquid level sensor.

Working principle: The photoelectric liquid level sensor is a new contact point liquid level measurement and control device developed using the principle of reflection and refraction of light at the interface of two different media. The working principle is that the product contains a near-infrared light-emitting diode and a photosensitive receiver. Light from the LED is directed into a lens on top of the sensor. When the liquid immerses the lens of the photoelectric liquid level switch, the light is refracted into the liquid, so that the receiver cannot receive or can only receive a small amount of light. By sensing this change in operating conditions, the photoelectric liquid level switch allows the receiver to drive the internal electrical switch to activate an external alarm or control circuit. If there is no liquid, the light from the LED is reflected directly from the lens back to the receiver.

It can be seen from the working principle: Photoelectric liquid level sensors are used to detect liquids, including stable substances, the interface between two immiscible liquids and the occurrence of deposits. Their work is based on changes in the transmission of infrared light emitted by infrared LEDs. Using high-energy infrared diodes and pulse modulation methods, light interference can be reduced. Optoelectronic level sensors, on the other hand, use high-intensity lasers that can inject dusty environments and notice liquid substances.

pros and cons:
Compact, high pressure, no moving parts and temperature capable, can notice trace amounts of liquid. Since the sensor needs to be in contact with the liquid requiring electrical power, certain wide substances may cause coating on the prism.

Next let's take a look at the capacitive liquid level sensor.
The capacitive liquid level sensor is a variable dielectric capacitor that uses changes in the measured medium surface to cause changes in capacitance. Used to detect changes in liquid level like mud and aqueous solutions. The sensor detects changes in liquid level by using a probe made of polytetrafluoroethylene insulated wire. The change in liquid level causes a change in capacitance. According to the detected capacitance value The size is used to determine whether the location of the sensor is in a water state or a water-free state. However, stainless steel probes are extremely responsive and therefore suitable for measuring particles of non-conductive matter or materials with low dielectric constants. These types of sensors are very easy to use and clean because they don't have any moving parts.

pros and cons:
One of the biggest features of the capacitive type is that it can detect changes in water level without touching the liquid. Therefore, when the container does not need to be opened and there is dirt, impurities, and sediment inside, it will not affect the test results.

So what are the advantages of "photoelectric liquid level sensor" compared to "capacitive liquid level sensor"?