Remote sensing and power lead loss


Sometimes, when a load draws high current, it leads to a voltage drop across the power terminals. Under these circumstances, the device under test or appliance could fail or there could be a system malfunction. Many embedded engineers are familiar with this anomaly. But you can prevent this by using remote sensing.

All you have to do is add a second wire- a sense wire. This will ensure the power terminals receive the correct voltage level. This is a good technique to get the most out of your custom power supply.

If you want to determine the voltage drop across the leads, multiply the power pulled by the load with the resistance of the terminals. What the remote sensing wire does is, it regulates the output voltage according to the voltage at the remote sensing input and not voltage at the output terminals.

The source’s output will also increase, more than that needed by the load, to compensate the voltage drop in the power lead. To benefit from remote sensing, you just have to supplement the system with a second wire set.

The extra cable is connected to the power terminals of the load and remote sensing input at power source. Don’t forget to connect the cable shield to the ground.