The Wonderful World of Kitchen Faucets
Touchless Faucets

Two significant components separate regular faucets from automated ones. They are solenoid valves and sensors.
A solenoid valve is a component that controls water discharge. And the sensors detect objects near the spout lip and send the signal to the valve to discharge. The sensor can be at the bottom of the spout or the lip of the spout. They might be infrared detectors, eco sensors, or motion detectors.
Infrared sensors look for heat signatures. While it works great with body parts, it isn't that good with inanimate objects. On the other hand, it could also be triggered by a hot pan or water in the sink. Eco and motion sensors detect sound and motion changes in their field of view.
Given the current COVID-19 pandemic, we cannot recommend touchless faucets enough.
Touch On Faucets

When hearing the name, many people mistakenly believe that a touch kitchen faucet is the exact opposite of a touchless kitchen faucet. In fact, these two devices are more similar to each other than they are to a traditional kitchen faucet. That's because both can be turned on and off without the use of a handle. This is done through the use of a solenoid valve that opens and closes automatically when triggered by the faucet's sensor.
There are some big differences between a touch faucet and a touchless faucet, though. A touch kitchen faucet, also called a "touch-sensitive faucet," turns on when a user touches it. This touch can occur anywhere on the faucet, including the handle or spout, and it can be done with a hand, wrist, forearm, etc., which is convenient when your hands are dirty. The on/off features are activated through the same small electrical charge of the human body that makes a touch screen work.
Pulldown Faucets

Pulldown faucets have a large gooseneck spout, and the head of the faucet comes out from the spout. A hose is inside the spout, which can be pulled out for more flexibility in washing. It has a locking mechanism that locks the head with the spout.