Automatic faucets combine four key components: Solenoid valve, electronic unit (infrared sensor), power source, and faucet body. Solenoid valve: Transforming electrical energy into motion, the solenoid physically starts and stops the water flow. Stern products use \"latching\" solenoids. The solenoid is initially energized to start the water flow, the plunger is driven into the range of a permanent magnet which in turn holds the plunger in the \"open\" position. In order to return the plunger into its original \"closed\" position the solenoid is once again \"pulsed\" but this time by reversing polarity. This operation conserves battery power, that’s why a latching solenoid can be used for electronic faucets powered by batteries or mains. Electronic unit: senses the presence of an object (the user’s hands) in front of the faucet and sends a signal to the solenoid valve to initiate the flow of water. When the object is no longer present, the electronic unit orders the solenoid valve to terminate the flow of water usually after a few seconds (delay out time). Power source: most of Stern models have the possibility to be powered by a regular 9V battery (Lithium or Alkaline) or by mains via a 9V transformer. Batteries and transformers are included with the product. Faucet body: Delivers the water. Stern puts special emphasis in design. Even if the faucet is electronic it must be in tune with the style of every specific place. Stern produces electronic taps with different styles to match every decorative theme.
