Low Cost 4-20 mA Calibrator

Specifications:

• Simple loop powered variable current source.
• Low voltage drop - less than 10 V with 820Ω load at 20 mA.
• Stable constant current control.
• Use in series with your multimeter.
• Simply connected in series with any DC power supply from 12 V to 32 V and the current through the unit is then controlled by the potentiometer.
• Current is independent of changes in the DC supply and the load resistance.