The **KFS-02-R** is a specific model of a **water flow sensor** (often categorized under flow switches). It is widely used in water heaters, cooling systems, and industrial fluid control to detect the movement of liquid and trigger electrical circuits. --- ### 1. Key Technical Specifications The electrical behavior of the KFS-02-R is centered around its ability to act as a bridge between fluid dynamics and electronic control systems. | Component / Parameter | Specification / Detail | | :--- | :--- | | **Sensor Type** | Magnetic Reed Switch | | **Switching Voltage** | Typically 100V - 250V AC/DC (Max) | | **Switching Current** | 0.5A to 1.0A | | **Contact Form** | Normally Open (NO) | | **Flow Rate Range** | 1.0 - 30 L/min (Standard variant) | | **Material** | Plastic/Polymer Housing with Brass inserts (model dependent) | --- ### 2. Internal Electronic Components The device operates on simple but reliable electromagnetic principles. It does not typically contain complex integrated circuits (ICs), making it highly durable. 1. **Magnetic Float:** Inside the pipe, there is a plastic piston or "shuttle" containing a permanent magnet. As water flows, the pressure pushes this float upward. 2. **Reed Switch:** This is the core electronic part located in the dry section of the housing. It consists of two ferrous metal blades hermetically sealed in a glass tube. 3. **Wiring Interface:** Standard two-wire output. Since it is a passive switch, it does not require a power supply to operate; it merely opens or closes a circuit. --- ### 3. Circuit Integration Example To use the KFS-02-R with a microcontroller (like an Arduino) or a relay, you should treat it as a momentary switch. ```cpp // Basic Arduino Logic for KFS-02-R const int flowSensorPin = 2; // Connected to one wire of KFS-02-R void setup() { pinMode(flowSensorPin, INPUT_PULLUP); // Use internal resistor Serial.begin(9600); } void loop() { int status = digitalRead(flowSensorPin); if (status == LOW) { Serial.println("Flow Detected: Switch Closed"); } else { Serial.println("No Flow: Switch Open"); } } ``` --- ### 4. Critical Usage Notes * **Inductive Loads:** If using the KFS-02-R to trigger a motor or a large pump directly, you **must** use a snubber circuit or a flyback diode. The reed switch inside can be welded shut by the back-EMF of an inductive load. * **Orientation:** These sensors are gravity-dependent. They are usually designed for vertical installation so the float falls back down when the water stops. * **Protection:** It is highly recommended to use this sensor to trigger a **Relay** or **SSR** (Solid State Relay) rather than carrying the full load of the appliance through the sensor's thin internal reed blades.