What Is a 0-100 mV Signal and When Should You Use It?

A 0-100 mV output is a low-level analog signal in which the transmitter's full pressure range is represented by a voltage swing of only 100 millivolts (0.1 V) — for example, 0 mV at zero pressure and 100 mV at full-scale pressure. It is typically a ratiometric signal, meaning the output scales with the transmitter's excitation voltage rather than being fixed in absolute terms. Choose it when you need very low power draw, are feeding an OEM circuit board or ADC directly, and can keep cable runs short and electrically quiet. Choose a higher-level output (4-20 mA, 0-5 VDC, 0-10 VDC, or 1-5 VDC) when the signal must travel any meaningful distance through an industrial environment.

BEC Controls Corp. lists 0-100 mV among the standard outputs offered on its custom differential, gauge, and vacuum pressure transmitters, alongside 4-20 mA, 1-5 VDC, 0-5 VDC, 0-10 VDC, and custom options, with pressure ranges from 0.5" WC to 1500 PSI.

What the 0-100 mV range actually represents

The "0-100 mV" describes the span of the output, not the pressure range. The transmitter maps its configured pressure range onto that 100 mV window:

• 0 mV = the low end of the pressure range (often zero, but not necessarily — a transmitter can be ranged to start above zero)
• 100 mV = the high end (full scale)

Because the span is so small, resolution depends heavily on the receiving device. A 12-bit ADC referenced to 100 mV gives roughly 0.024 mV per count; the same ADC referenced to 5 V would waste most of its range on a 100 mV signal. This is why millivolt outputs are usually paired with a matched amplifier or a high-resolution, low-reference ADC rather than a generic 0-10 V input card.

Why millivolt outputs exist

Three characteristics drive the choice of a 0-100 mV signal:

Low power consumption. Driving a 100 mV signal into a high-impedance input takes far less energy than sourcing 4-20 mA through a loop or generating a 0-10 V rail. This matters for battery-powered or energy-harvesting devices.

Ratiometric operation. Many millivolt transmitters scale their output proportionally to the supply (excitation) voltage. If the supply sags, the output sags by the same ratio, and a ratiometric ADC using the same supply as its reference cancels the error. This is common in OEM sensor front-ends.

Direct interface to OEM electronics. A device with its own signal conditioning, microcontroller, or instrumentation amplifier can accept the raw millivolt signal and apply gain, filtering, and linearization where it's needed — avoiding an extra conversion stage.

How 0-100 mV compares with other analog outputs

The key trade-off: millivolt signals are the most susceptible to electrical noise and ground offsets, but they are also the cheapest and lowest-power to generate. Higher-level voltage outputs improve noise margin at the cost of a stiffer output stage; the 4-20 mA current loop is the most robust because current is unaffected by cable resistance and the live zero (4 mA) lets the receiver detect a broken wire.

When to choose 0-100 mV

Pick a 0-100 mV transmitter when most of these are true:

• The signal runs only a short distance — typically within the same enclosure or between adjacent boards.
• The receiving circuit has a high-impedance input, an instrumentation amplifier, or a ratiometric ADC referenced to the same supply as the transmitter.
• Power budget is tight (battery-powered or loop-powered from a small source).
• You are an OEM integrating the sensor into your own product and can control grounding, shielding, and gain.
• You need a custom pressure range and want the simplest possible analog front end.

Avoid it when the signal must cross a noisy plant floor, when the receiver only accepts 4-20 mA or 0-10 V, or when you cannot guarantee a stable, low-noise excitation source.

Practical wiring and troubleshooting notes

Shielding and grounding. Because 100 mV is easily corrupted, use shielded twisted pair, ground the shield at one end only (usually the receiver), and keep the signal return separate from power grounds where possible.

Stable excitation. If the output is ratiometric, any ripple or drift on the excitation supply appears directly in the reading unless the ADC shares that reference. Use a clean, regulated supply and verify the transmitter's specified excitation range.

Short runs. Keep cable length to the minimum the application allows. Every extra foot adds capacitance, picks up more noise, and introduces more ground-offset error.

Signal conditioning. Expect to add gain and filtering at the receiver. A differential input amplifier with a low-pass filter is a common front end; a single-ended input referenced to a noisy ground will usually perform poorly.

Verification. With zero pressure applied, confirm the output sits at the low end of the span (accounting for any offset or live-zero the transmitter specifies). Apply a known mid-scale pressure and check that the output is approximately half the span. If the reading drifts with supply voltage, the signal is ratiometric and the receiver must reference the same supply.

Common failure modes. Erratic readings usually trace to a missing or poor shield connection, a ground loop between transmitter and receiver, an excitation supply that is out of the specified range, or a receiver input impedance that is too low and loads down the output.

Where this fits in the BEC Controls lineup

BEC Controls Corp. builds custom differential pressure, gauge pressure, and vacuum transmitters for OEMs, resellers, contractors, and end users, and lists 0-100 mV as one of the available outputs along with 4-20 mA, 1-5 VDC, 0-5 VDC, 0-10 VDC, and custom configurations. Pressure ranges span 0.5" WC to 1500 PSI, and the company states that customization is free and that same-day shipping is available. If your application needs a millivolt-level, ratiometric output for a short-run OEM interface, that is the configuration to specify; if it needs to survive a long industrial cable run, specify 4-20 mA instead.