10V Analog Output Voltage

This application note explains how to obtain a 0 to 10V analog output voltage using the EMANT300. This circuit is used in a proportional valve application. The proportional valve control flow rates from 1.4 to 5m3/h. The variable opening of the cross section is changed proportional to the 0-10V input signal

The analog input range required by the proportional valve is 0 to 10V whereas the analog output of the EMANT300 USB DAQ module is a current from 0 to 1mA (see EMANT300 specs).

The following non inverting opamp circuit is used to convert the 0 to 1mA output to 0 to 10V output.

analog output equation

The opamp LM2904 is connected in a negative feedback configuration. V- is given by

analog output equation

IDAC is the current output of the EMANT300. V+ is given by

analog output equation

In negative feedback, you can assume that V+ = V- Combining both equations gives

analog output equation

Substituting the component values from the schematic into the equation, gives the following relationship

analog output equation


  1. The supply voltage to the opamp should not exceed 32V for the LM2904.
  2. The resistors used should be 1% or better.

C# code

using System; using System.Collections.Generic; using System.Text; using Emant; namespace Vout { class Vout { static void Main(string[] args) { double volt; string input; Console.WriteLine("Output Voltage 0 - 10"); input = Console.ReadLine(); volt = Convert.ToDouble(input); Emant300 DAQ = new Emant300(); DAQ.Open(); // 10V requires 1mA output current DAQ.WriteAnalog(volt/10); DAQ.Close(); } } }