Comparison

4–20 mA vs 0–10 V: Which Analog Signal Should You Use?

4–20 mA resists noise and long cables and flags a broken wire. 0–10 V is simple but noise-prone. Compare length, grounding and fault detection.

Controls & Instrumentation · Last reviewed October 17, 2026

Short answer: use 4–20 mA for field instruments, long cable runs and electrically noisy plants, because it is robust and tells you when the wire is broken. 0–10 V is acceptable for short runs inside panels and in building controls, where simplicity and low cost matter.

	4–20 mA	0–10 V
Signal type	Current, the same in all parts of the loop	Voltage, which can drop in the wiring and pick up noise
Cable length	Long runs are fine, up to the loop compliance limit	Best for short runs
Noise immunity	High, because the receiver has a low impedance and the current is not changed by noise	Lower, because the receiver has a high impedance that picks up interference
Fault detection	The live zero means 0% is 4 mA, so 0 mA (a broken wire) is detectable	A zero reading can be a true zero or a broken wire
Powering the device	A 2-wire transmitter can be powered from the loop itself	The device needs a separate power supply
Input compatibility	The receiver uses a shunt resistor, such as 250 Ω for 1 to 5 V	High-impedance input, often 100 kΩ or more
Grounding	Less sensitive, but one point of the loop should be grounded	Sensitive to ground potential differences
Multiple receivers	Wired in series, and the sum of their resistances counts	Wired in parallel, if the source can drive them
Cost and ease	Slightly more costly, common in industrial plants	Cheap and simple, common in HVAC controllers

Loop compliance

A current loop works while the supply can drive the current through all the resistances. For a 24 V supply and a transmitter that needs at least 10 V at its terminals, the largest total loop resistance (receiver and wire) at 20 mA is:

(24 − 10) V ÷ 0.020 A = 700 Ω

A 250 Ω receiver leaves 450 Ω for the cable. At about 6.4 Ω per 1,000 ft for 18 AWG, a round trip of several thousand feet is still fine. Long runs fail through noise first with 0–10 V, and through loop compliance only at the extreme with 4–20 mA.

How to choose

Check what the device and the input module support. Many sensors and controllers support only one.
Estimate the cable length and the electrical noise along the route (drives, motors, power cables).
Decide how important broken-wire detection is.
Check whether the sensor needs loop power, and the supply available.
Keep the whole signal chain consistent, and document the ranges.

Common mistakes

Running 0–10 V signals for hundreds of feet beside power cables.
Forgetting the shunt resistor: reading a current signal with a voltage input gives nothing.
Mixing 0–20 mA and 4–20 mA scaling.
Grounding both ends of a signal shield and creating a ground loop.

Related tools and labs

Calculators, labs and simulators are part of the All-Access Pass.

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Questions

Why does 4–20 mA start at 4?

So that a loop-powered transmitter has current to run on at zero measurement, and so that a failure to 0 mA is clearly different from a valid zero reading.

Can I convert between them?

Yes. Signal converters or a shunt resistor change a current to a voltage. A converter can also isolate the two sides.

Educational material. Examples use simplified, hypothetical inputs and are not a design, a construction document or professional engineering advice. Confirm requirements with the codes and standards adopted where the work is built and with a licensed engineer.

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