Understanding remote sense in today’s power supplies

In today’s power-supply designs, even small wiring and connector resistances can distort the voltage that actually reaches the load. As systems push tighter tolerances and higher currents, these drops become harder to ignore.

Remote sense provides a straightforward way to correct them by letting the supply monitor the voltage at the load itself and adjust its output accordingly. Understanding how this mechanism works—and how to apply it properly—is essential for maintaining stable, accurate rails in modern designs.

Local sense vs remote sense: Where you measure matters

Most power supplies regulate their output using local sense—monitoring voltage at the supply’s own output terminals. This works fine in ideal conditions, but in real systems, the path from supply to load includes resistance from wires, connectors, and circuit-board traces. As current increases, even small resistances can cause significant voltage drop, meaning the load receives less than intended.

Remote sense solves this by relocating the feedback point to the load itself. Instead of trusting the voltage at the supply’s output, it uses a separate pair of sense wires to measure the voltage at the load terminals. The supply then adjusts its output to compensate for any drop along the way, ensuring the load sees the correct voltage—even under dynamic or high-current conditions.

This simple shift in measurement point can dramatically improve regulation accuracy, especially in systems with long cables, high currents, or sensitive loads. Many benchtop and lab-grade power supplies now include this feature, often with a front-panel or software-selectable option to toggle between local and remote sense. When testing precision circuits or powering remote loads, enabling remote sense can make all the difference.

Figure 1 Simplified schematic illustrates a remote-sense setup with external output and sense wires. Source: Author

As a sidenote on what local sense really does, it seems many benchtop power supplies now include a simple switch—or sometimes local-sense jumpers—to select between local and remote sense. In local-sense mode, the supply regulates using the voltage at its own output terminals.

Switching to remote sense hands regulation to the separate sense leads, allowing the supply to track the voltage at the load instead. This selectable mechanism lets you match the regulation method to the setup—local sense for short leads and quick tests and remote sense when wiring losses matter.

Figure 2 Wiring diagram shows a power supply with local-sense jumpers installed. Source: Author

Put simply, for a local-sense configuration, you install the local-sense jumpers so that the Sense + and Sense – terminals are tied directly to the corresponding + and – output terminals on the power supply’s output connector. For a remote-sense configuration, all local sense jumpers are removed, and the Sense + and Sense – terminals are routed externally to the matching + and – points at the load or device under test (DUT).

Note at this point that power supplies with a local/remote sense selector switch don’t require separate local sense jumpers. That is, power supplies equipped with a physical or electronic local/remote sense switch (or a digital configuration setting) utilize internal circuitry to bridge the sense lines to the output terminals. This eliminates the need for the external metal jumpers or wire loops typically found on the barrier strips of older or simpler power supplies.

4-wire sensing: More sensible pointers on remote sense

Starting this session with a cautionary note, always verify the selector switch position and all sensing connections before enabling the output. Setting the switch to Remote without sense wires attached can trigger the feedback loop to detect zero voltage and attempt to compensate. This often forces the power supply to its maximum voltage, potentially damaging your equipment even if physical jumpers are absent.

Furthermore, any noise captured by the sense leads will be reflected at the output terminals, potentially degrading load regulation. To minimize electromagnetic interference (EMI) from external sources, use twisted-pair wiring or ribbon cables for the sense connections.

Because these high-impedance leads carry negligible current, thin-gauge wire is sufficient for this purpose. In high-noise environments, shielded cabling may be necessary; if used, ensure the shield is grounded at the power supply end only and never utilized as a current-carrying sensing conductor.

As a quick aside, it appears that many power supplies now implement some form of smart sense detection as a fail-safe. Since a floating sense connection can create a hazardous open-loop state, these systems protect the hardware by shutting down if the leads are disconnected—whether that happens during live use or at initial startup.

In practice, many modern programmable power supplies use auto-sense technology to monitor sense terminals and automatically engage remote sensing when external leads are detected. To ensure stability, these units include internal protection resistors—often called fallback resistors—connecting the output and sense terminals.

These resistors provide a secondary feedback path that allows the supply to default safely to local sensing if leads are missing or accidentally disconnected. This hardware redundancy prevents a dangerous open-loop overvoltage condition, protecting the load from upsurges caused by wiring failure or human error.

Just a sidewalk, ordinary yet essential, becomes a metaphor for design simplicity. On a workbench scattered with piles of discrete electronic components, it’s equally instructive and rewarding to attempt the design of an entry-level remote-sense power supply.

Experimenting with various operational amplifier configurations—specifically differential and error amplifier circuits—alongside voltage references demonstrates how feedback loops maintain precise regulation under dynamic loads.

Such a hands-on approach not only highlights the critical aspects of stability and compensation but also provides valuable insight into the trade-offs between component selection, circuit topology, and overall performance. These complexities are left for the reader to explore intentionally.

Virtual remote sense in practice

Jumping to a quick coffee break, let us touch on virtual remote sense (VRS). This clever technique emulates the benefits of true remote sensing without the extra wiring, helping designers maintain regulation accuracy while simplifying layouts.

Several well-known ICs in the Analog Devices’ portfolio—originally developed by Linear Technology—have embraced VRS to make implementation straightforward: LT4180, LT8697, and LT6110 are prime examples. Each integrates features that reduce voltage drops across traces and connectors, ensuring stable supply rails even in demanding applications.

Because these devices employ different methods to achieve VRS, a thorough review of their datasheets is strongly recommended to understand the nuances and select the right fit for your design. Exploring these solutions hands-on could be the key to unlocking cleaner, more reliable power delivery in your next project.

T. K. Hareendran is a self-taught electronics enthusiast with a strong passion for innovative circuit design and hands-on technology. He develops both experimental and practical electronic projects, documenting and sharing his work to support fellow tinkerers and learners. Beyond the workbench, he dedicates time to technical writing and hardware evaluations to contribute meaningfully to the maker community.

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