Introduction: Loop Calibrator ( 0 to 20 MA / 4 to 20 MA) Using Mosfet IRF840. Constant Current Source

By Trinity automation
About: Iam instrumentation and controls professional working in Emirates global aluminium (EGA) located at Dubai. I'm circuit designer and software developer by passion. Whatsapp (+91)9163954390

In this instructable I am going to demonstrate loop calibrator. A loop calibrator is a device that generates constant current of 0 to 20 mA used to simulate instrumentation loops in indistry.

Supplies

  1. Mosfet IRF840
  2. Suitable heatsink.
  3. 330 ohms 1 watt -- 2 pc
  4. 100 ohms 1 watt -- 1 pc
  5. 10K wirewound potentiometer.
  6. 10K trim Potentiometer.
  7. 1K 1/4 watt resistor
  8. 10K 1/4 watt resistor

Step 1:

Wire the circuit as shown in circuit. refer attached video for further details.

Connect to required loop and test as current source or simulator.