Weight goes on, an aluminium beam bends, and the gauges riding on that beam turn the bend into a handful of millivolts. Multiply by a scale factor and you have kilograms.
Every load cell datasheet carries a line that looks like the important one. Usually it is nonlinearity, because that is the number buyers compare. On an economical sensor built for weighing, it is frequently the wrong number to be looking at — not because it is untrue, but because something else on the same page is larger by an order of magnitude and decides what you actually get.
Work out which specification your application exposes. That is the whole exercise, and it produces different answers for different products. A part with excellent linearity and a wide temperature coefficient is a precision sensor in a temperature-stable room and a mediocre one on a loading dock. A part with a large zero offset is irrelevant in a device that tares before every reading and a serious problem in one that cannot. Neither fact is hidden; both are simply further down the page than the number people compare.
On this class of sensor, temperature usually governs. Run the arithmetic rather than trusting an impression. A tenth of a percent of nonlinearity is a fixed, modest error. A temperature coefficient of a few hundredths of a percent per degree becomes a percent or more across an ordinary daily swing — several times the linearity figure, from a variable nobody thinks of as an accuracy specification. Whether that matters depends entirely on whether your product's environment moves.
And the zero offset governs your electronics. A weighing sensor's unloaded output is not expected to be near zero, because the design assumption is that firmware tares it. What that means for a designer is that the front end has to accommodate the offset and the signal, and on a low-output sensor the offset can be the larger of the two by some margin. Gain set from the span alone will saturate before anything is placed on the scale.
None of that makes a sensor bad; it makes it suited to a purpose. A bench scale that lives indoors and is tared before every weighing is exposed to almost none of it, and gets genuinely good linearity for very little money. A device that self-heats, sits outdoors or cannot re-zero is exposed to all of it. Same sensor, same datasheet, opposite conclusions.
Sensors of this kind belong in bench, platform and hopper scales, check-weighers in food and pharmaceutical production, filling and packaging machinery, conveyor weighing, tank and silo inventory measurement, laboratory balances, and OEM equipment where a weight or force reading is one function among many.
The bridge is conventional. What repays attention on this part is the signal budget, because the numbers are smaller than most designers expect and three of them interact.
Start with how much signal there actually is. Rated output is 0.5 mV/V, and the excitation is 5 VDC with 8 VDC the maximum. That gives a full-scale span of about two and a half millivolts, rising to four if you run at the ceiling. Published weigh-scale reference designs generally work from a 2 mV/V assumption, which at 5 volts would be ten millivolts — so the signal here is a quarter of what the standard worked example starts from, and the resolution problem is correspondingly harder. It is entirely workable with a modern sigma-delta converter; it is not workable with an approach designed around a conventional load cell without checking the arithmetic first.
Then look at the offset, because it is bigger than the span. Zero balance is specified at up to one millivolt per volt on a sensor whose rated output is half a millivolt per volt. In plain terms, the unloaded output can be about twice the entire full-scale signal, in either direction. This is normal for a weighing component and it is not a defect — but it means the input range of your front end must cover the offset window first and the measurement second. Size your gain from the offset, not from the span, or a perfectly good sensor will peg your amplifier with an empty pan.
Sensitivity varies from unit to unit, so span has to be calibrated. Rated output carries a ±10% tolerance, which means two sensors from the same box can differ from each other by a fifth of full scale. A finished instrument hides this behind its certificate. A component does not, so an end-of-line span calibration against a known mass is not optional in any product that reports a number a user acts on. A tare handles the offset; only a span calibration handles this.
Excitation is low, and capped. Five volts nominal with an eight volt maximum is unusual in a catalogue where ten volts is standard, and it suits battery and board-level designs. Note that the cap limits how much signal you can buy back by raising excitation. The neat answer used by most modern weigh-scale designs is a ratiometric arrangement, where the same reference that excites the bridge also provides the converter's reference — supply variation then cancels rather than appearing as measurement error.
Temperature coefficients are the widest in our range, and deliberately so. Zero and output each move by a few hundredths of a percent per degree Fahrenheit across a compensated band running from below freezing to just above forty Celsius. That band is chosen for equipment that lives in cold stores, vehicles and unheated buildings rather than laboratories, and the coefficient is the price of building an economical aluminium sensor to cover it. Calculate the drift over your own operating swing rather than assuming it away, and where a product self-heats, tare once it has settled rather than at switch-on.
Overload margin is the best we offer. Safe overload is 200% of rated output, against 150% almost everywhere else. On equipment that gets loaded by hand, leaned on or filled carelessly, that extra margin is worth having and it is a genuine point in this sensor's favour.
Choosing an economical weighing sensor is largely a matter of being honest about the environment and the electronics. Our application engineers would far rather have that conversation at the design stage than after a first article has been built.
Describe where the product will live before anything else. Indoors at stable room temperature, tared before each use, and this sensor gives you a tenth of a percent of linearity for very little money. Outdoors, in a chiller, in a vehicle, or in a housing that warms under its own electronics, and the temperature coefficient becomes your dominant error. Neither answer is wrong; they simply lead to different products, and the question takes ten seconds to ask.
Ask whether the product can re-zero. This is the question that decides how much the offset and the drift actually cost you. A scale that tares before every weighing is insulated from a great deal. A sensor buried in a machine that powers up once and runs for a month is not, and it needs either a stable environment or a periodic auto-zero routine designed in.
Size capacity in the units your application uses. The range is specified in kilograms — 1, 2, 5 and 10 kg, or roughly 2.2 to 22 lb — which is unusual in our catalogue and often exactly what an OEM weighing design wants. All four are the same price, so pick the smallest that covers your maximum, remembering that accuracy figures are proportions of rated output and that a 10 kg sensor asked to resolve grams is spending its resolution on capacity you never use.
Settle the mounting and the load path early. How the beam is clamped and where the force arrives are design decisions with measurable consequences, and they are yours rather than ours on a component. If your design puts a platform or a pan on the sensor rather than applying force at a defined point, tell us at the enquiry — that arrangement has particular requirements and it is worth confirming the right part for it before you build a fixture around one.
Plan the front end around the numbers above. Input range wide enough for the offset, gain set accordingly, a converter with the resolution the small span demands, a ratiometric reference if you can arrange one, and an end-of-line span calibration in your production process. None of that is difficult; all of it is much easier to design in than to retrofit.
Then decide what reads it. Plenty of OEM designs take the bridge straight into their own converter. If yours will not, an amplifier signal conditioner module puts the output into territory a controller can use, and a digital display earns its place on the bench while you are still developing. Check that whatever you choose is configured for a 0.5 mV/V sensor rather than assuming the usual 2 mV/V, and Cal-Teds plug and play is worth asking about where sensors are swapped during development.
Tell us the weight range, the environment, whether the product can tare and what the reading is used for, and we will help you settle on a capacity and confirm this is the right family. We hold all four ranges, and academic and research orders qualify for a discount.
EBB Series Load Cell Applications.
The Transducer Techniques EBB Series economical bending beam force sensors, available in 1, 2, 5 and 10 kilogram capacities, serve industrial and OEM contexts requiring force measurement and weighing.
- Industrial Weighing Systems: EBB Series sensors are used in bench, platform, and hopper scales.
- Check-Weighing Systems: These sensors are used in check-weighing systems in food, pharmaceutical, and manufacturing operations.
- Conveyor Scales: EBB Series sensors are integrated into conveyor scales for continuous weight monitoring.
- Filling and Packaging Machinery: These sensors are used in filling and packaging machinery in food and beverage production.
- Material Handling Equipment: EBB Series sensors are used in material handling equipment including lift trucks and pallet jacks.
- Tank and Silo Weighing: These sensors are applied to tank and silo weighing for inventory management.
- Test Rigs: EBB Series sensors provide force measurement in test rigs for fatigue and strength testing.
- Laboratory Balances: These sensors are used in laboratory balances for research and scientific applications.
- Medical Device Instrumentation: EBB Series sensors are used in medical device instrumentation requiring precise force measurement.
- Custom Machinery and OEM Equipment: These sensors are integrated into custom machinery and OEM equipment for specialized applications.
- Quality Control: EBB Series sensors are used in quality control operations across various industries.
- Automotive Testing: These sensors are used in automotive component testing and validation.
The Transducer Techniques EBB Series bending beam force sensors provide reliable and cost-effective solutions for a wide range of industrial and OEM applications where precise force measurement and weighing are essential.
Frequently Asked Questions
What capacities does the EBB Series cover and what does it cost?
Four ranges, specified in kilograms: EBB-1 at 1 kg (2.2 lb), EBB-2 at 2 kg (4.4 lb), EBB-5 at 5 kg (11 lb) and EBB-10 at 10 kg (22 lb). All four are $160. Metric capacities are unusual in our catalogue and often exactly what an OEM weighing design is working in. Since the price is flat and the accuracy figures are proportions of rated output, choose the smallest range that comfortably covers your maximum weight.
Why is the rated output only 0.5 mV/V?
It is the lowest in our range, and it is a consequence of building an economical aluminium bending beam. At the nominal 5 VDC excitation it works out at about two and a half millivolts across the full range — where a typical 2 mV/V load cell at the same excitation would give ten. Published weigh-scale reference designs generally start from that higher figure, so if you are following one, check the resolution arithmetic against the smaller number. It is entirely workable with a modern high-resolution converter; it is not something to discover after the board has been laid out.
The zero balance is ±1 mV/V but the output is only 0.5 mV/V. Is that right?
Yes, and it is the most important number on the page for anyone designing the electronics. The unloaded output can be about twice the entire full-scale signal, in either direction. That is normal for a weighing component, because the design assumption is that your firmware tares it — but it means the input range of your amplifier has to accommodate the offset before it accommodates the measurement. Set the gain from the span alone and a perfectly healthy sensor will saturate your front end with nothing on the scale.
What does the ±10% tolerance on rated output mean for my design?
It means unit-to-unit sensitivity varies, so two sensors from the same batch can differ by up to a fifth of full scale between them. On a finished instrument the calibration certificate absorbs that; on a component it does not, so any product that reports a number a user acts on needs an end-of-line span calibration against a known mass. This is a separate step from taring: a tare removes the offset, and only a span calibration corrects the sensitivity. Build both into your production process.
How accurate is the EBB Series?
Nonlinearity and hysteresis are each 0.1% of rated output and nonrepeatability is 0.05% — genuinely good figures for an economical part, matching several of our industrial products. The honest caveat is that on this sensor those are not usually the limiting numbers. The temperature coefficients are 0.06% per °F on both zero and output, so a twenty degree change costs you around 1.2%, more than ten times the linearity figure. In a temperature-stable installation you get the linearity; where the environment moves, temperature is your error budget.
What excitation does the EBB need, and can I run it higher?
5 VDC nominal, with 8 VDC the maximum — lower than the 10 VDC used across most of our range, which suits board-level and battery designs. Output is proportional to excitation, so running at 8 V gives you about four millivolts of span instead of two and a half. Do not exceed the maximum. The arrangement most modern weigh-scale designs use is ratiometric: the same reference that excites the bridge also feeds the converter, so any variation in the supply cancels out instead of showing up as a measurement error.
What is the EBB made from, and what is its overload rating?
Aluminium alloy, which is the conventional and correct choice for low-capacity weighing beams — light, stable enough for the accuracy class, and inexpensive to machine. Safe overload is 200% of rated output, which is the highest figure in our entire load cell range; almost everything else is 150%. On equipment that gets loaded by hand, leaned on or filled carelessly, that extra margin is a genuine practical advantage and worth weighing in the sensor's favour.
What temperature range is the EBB compensated over?
14° to 104°F compensated, with a safe range of 14° to 140°F — a band that reaches well below freezing, unlike the 60° to 160°F our industrial products use. That suits cold stores, vehicles, unheated buildings and outdoor equipment. The trade is the coefficient: 0.06% per °F on both zero and output means you should calculate the drift across your own operating swing rather than assume it away. Where the product self-heats, take the tare after it has reached working temperature rather than at switch-on.
What lead wire is fitted?
Six inches of 30 AWG pigtail leads — sized to reach a circuit board a few centimetres away, not an instrument across a room. Anything you add becomes part of the measuring circuit, and wire this fine carries appreciably more resistance per foot than industrial load cell cable, so a long extension costs sensitivity on a sensor that has little to spare. Solder or terminate close to the sensor, provide strain relief so nothing pulls on the leads themselves, and tell us if your electronics are further away than a short run.
Can I use an EBB in a platform or bench scale?
Weighing systems of that kind are listed applications, but there is a design question worth settling first. Scales where a platform sits on a single sensor depend on the reading being the same wherever on that platform the load is placed, and that behaviour comes from a specific corner-compensated construction rather than from bending beams generally. Tell us the platform size and how the load will land, and we will confirm which of our low capacity bending beam products is right for it — it is a quick conversation and a genuinely consequential one.
Questions From The Field
My amplifier saturates with nothing on the scale.
Almost certainly the zero offset rather than a fault. The specification allows an unloaded output of up to twice the full-scale span, in either direction, and a front end whose gain was calculated from the span alone will run out of headroom before any weight is applied. Two fixes, and most designs use both: widen the input range so the offset window fits comfortably inside it before gain is applied, and remove the offset in firmware with a tare rather than trying to trim it away in hardware. Check the raw bridge output with a millivolt meter first — if it sits within the specification, the sensor is fine and the front end needs revising.
Two sensors read differently under the same weight.
Expected, and the reason is the tolerance on rated output. Sensitivity is specified at 0.5 mV/V with a ±10% band, so two units can genuinely differ by a fifth of full scale. That is normal for a component and the answer is a span calibration on each assembled unit against a known mass, not a shared nominal scale factor. If you are building more than a handful of products, make that calibration a step in your production process — retrofitting it later means recalling and re-verifying everything already shipped.
The reading drifts through the day even though nothing changes.
Compare it against the temperature coefficients before looking anywhere else. At 0.06% per °F on both zero and span, an ordinary daily swing in an unheated building or a housing that warms under its own electronics produces exactly the pattern you describe, and it is the sensor behaving to specification rather than failing. Three practical responses: tare once the equipment has reached working temperature; add a periodic auto-zero routine if the product runs unattended; and if the environment genuinely moves a great deal and the reading has to hold, tell us, because a more tightly compensated sensor may be the right answer.
Do I need to calibrate every unit, or can I use the nominal sensitivity?
It depends on what your product claims. Working from the nominal figure is reasonable where you need a repeatable indication rather than a stated weight — a fill-level check, a presence detection, a threshold. Where the display shows a number a user acts on, the ±10% output tolerance makes per-unit span calibration necessary, and calibrating the assembled product also captures your own mounting and electronics rather than the sensor alone. A tare is required either way; that is a separate matter and no design should skip it.
Can I run the sensor at a lower excitation to save power?
Yes, and it is a common approach in battery-powered designs. Output is proportional to excitation, so halving the voltage halves the signal — a straightforward trade of resolution for current rather than anything that harms the sensor. On a part with only half a millivolt per volt to begin with you have less to give away than usual, so check the arithmetic against your converter's noise floor before committing. Pulsing the excitation and sampling between pulses is often a better route to the same saving, and a ratiometric reference keeps the measurement honest whichever you choose.
How should the beam be mounted?
Clamped firmly at one end against a flat, rigid surface, with the remainder free to bend and the force applied where the design intends. Three things commonly go wrong. A mounting face that is not flat pre-loads the beam and shows up as a large or wandering zero. Over-tightening small fasteners into an aluminium beam can distort it. And a housing that touches the beam anywhere along its free length — or a wire routed across it — will add its own stiffness and change the reading. If you are designing the fixture yourself, get the clamped end flat and solid first; most other problems follow from that one.
Something heavy was dropped on it. How do I know if it survived?
The 200% safe overload rating gives more margin than most sensors, but an impact can exceed it easily. Start with the unloaded output: measure the raw bridge voltage and check it against the ±1 mV/V zero balance specification. A reading that has moved well outside that band, and stayed there, points to permanent set in the beam. Then measure bridge resistance across the excitation pair and compare with the 350 ohm nominal — a wildly different value or an open circuit indicates a damaged gauge or lead. Finally check that a known weight still reads correctly, since an overloaded beam can zero acceptably and still have lost its span.
Can I use this outdoors or in a wash-down area?
The compensated range reaching below freezing means the temperature side of outdoor use is covered better than most of our range, and cold stores and vehicles are sensible applications. Moisture is a different question. This is an economical component with pigtail leads rather than a sealed industrial instrument, so direct wash-down, driving rain and condensing environments are not what it is built for — and moisture reaching strain gauges shows up as slow drift rather than obvious failure, which makes it easy to miss. Describe the environment to us and we will tell you honestly whether this family suits it or whether a sealed product is the right answer.