Complete electrical isolation between power and signal. ✅ Why Use 4-20 mA?

The 4 mA floor allows the system to distinguish between a "zero" reading and a broken wire (0 mA). 🛠️ Main Components A functional circuit consists of four essential parts: Sensor/Transducer: Measures the physical variable.

Can run hundreds of meters without signal loss (unlike voltage, which drops over distance).

A device like a PLC or indicator that reads the signal, usually by passing the current through a 250 Ohm resistor to create a 1-5V drop for processing. 📐 Connection Types (Wiring Schemes) 2-Wire Connection (Passive)

Converts the sensor signal into the 4-20 mA current.

The most common setup where the transmitter is powered by the loop itself. Two wires carry both power and the signal. Benefit: Saves cable costs and simplifies installation. 3-Wire Connection (Active)