In this article, we discuss about How to Convert Current to Voltage using Resistor with different examples like 0-20 mA to 0-10 VDC Conversion, 4-20 mA to 2-10 VDC Conversion, 0-20 mA to 0-5 VDC Conversion.
Convert Current to Voltage
It is extremely simple to measure 0-20ma signal with a device that will measure only Voltage inputs. If Voltage input module available will accept a 0-10Vdc signal, but may not accept a 0-20ma signal directly.
Basically, Ohms law is used to calculate a resistor value in order to convert the 0-20ma signal to a voltage.
Example : 0-20 mA to 0-10 VDC Conversion
Ohms law states: R = V/I where V is the Voltage, I is the current and R is the resistance
RÂ = 10V/0.020A =Â 500 Ohms
V = I*R = 0.020*500 = 10V
Example : 4-20 mA to 2-10 VDC Conversion
Ohms law states: R = V/I where V is the Voltage, I is the current and R is the resistanceÂ
RÂ = 10V/0.020A =Â 500 Ohms
V = I*R = 0.020*500 = 10V
Example : 0-20 mA to 0-5 VDC Conversion
Ohms law states: R = V/I where V is the Voltage, I is the current and R is the resistanceÂ
RÂ = 5V/0.020A =Â 250 Ohms
V = I*R = 0*250Â Â Â Â Â Â Â = 0V
V = I*R = 0.020*250 = 5V
Note:-
- To avoid damage you must ensure that the external current source has short-circuit protection in all conductor cases.
- The external resistor is a source of error because of its dependency on temperature and its inaccuracy.
- In order to obtain measuring results that are as precise as possible it is recommended to use resistors with tolerances that are as small as possible.
Credits : myplctechnology blog