current to Voltage and Voltage to Current converter


Thread Starter


Dear All,
I want to know how to convert current from transmitter (4-20mA) to 1-5 Volt as input ADC. and how to convert Voltage to current from DAC to Control Valve.
Its enough using Resistor? or you have efficient and effective idea to convert this.
Thanks & Regard
TR. Biyanto


Mike Trombley

The best way to convert analog signals is to use a signal conditioner. Red Lion, Wilkerson and Action Instruments are great ones to use. I do this fairly often with AC drive systems and have found using resistiors limits your ablitiy to tune the circuits. Going from 4-20ma loop to a 1-5v signal is easier than 0-10v signal to 4-20ma loop. So if it is for more than test or experiment I would use a signal conditioner.
Good luck
Your set up looks odd. If you had an instrumentation system, it would be matter of appropriate I/O card.
1: 4_20 mA closed across 250 Ohms delivers 1_5 volts.
2: You need a voltage to current the output


Mark Mullins

Current to voltage is easy it just requires a 250 resistor in the 4-20mA loop this gives 20mA = 5V and 4mA = 1V. The input to your ADC goes across the resistor.

Mark Mullins
Microtech Electronics

michael windberger

Dear Mr. Mullins
I am very interested in an I/U-, U/I-Converter in the area of mV/V and mA . I have searched for your homepage but I haven't found one. Can you tell me where I can find your homepage.

Sincerly Michael Windberger

Try the Action Instruments Ultra SlimPak G408.

It will provide Voltage/current scaling, isolation, noise reduction and signal drive.
It requires a 9-30VDC power supply, seperate from your control signal.

Can convert Voltage or Current to Current or Voltage.

check out

how can i design a voltage to current converter by using operational amplifier to convert from (0-5v) to (4-100mA).