Semiconductor Technology

Article Summary.

The vast majority of the personal breathalyzers sold in pharmacies, mass market retailers and through the internet use “semiconductor technology” for sensing and measuring the breath alcohol content (BAC). Semiconductor devices are inappropriate for those interested in BAC measurement. This article explains why semiconductor breathalyzers should not be trusted for accurate and reliable BAC measurement.

What is semiconductor breathalyzer technology?

In semiconductor breath testers the alcohol sensor is formed from an inexpensive bead of tin metal oxide which must be heated to around 300 °C in order to function. A voltage is applied to produce a current across the sensor. When alcohol and other airborne substances contact the sensor, the resistance changes and so too the electrical current. The change in current is used to measure the breath alcohol content (BAC).

How selective are semiconductor alcohol sensors?

The answer is, not very. The tin oxide sensor cannot distinguish between alcohol and other airborne substances such as gasoline vapor, cigarette smoke, hairspray, breath acetone and a wide variety of other airborne substances. These other substances alone or mixed with breath alcohol will also trigger the sensor easily causing what’s called “false positives.” In other words, the device will sense alcohol even when none is present.

Semiconductor breathalyzers are short lived.

The more you use a semiconductor breathalyzer the shorter its lifespan and the more inaccurate it becomes. Semiconductor sensors rarely last longer than a year because the sensor is easily contaminated by airborne contaminants such as cigarette smoke. Additionally, sensor saturation with alcohol can rapidly destabilize the semiconductor device and throw-off the results.

Semiconductor Accuracy and Precision

Semiconductor technology is inherently inaccurate. At best these breathalyzers can detect the presence of alcohol but they can cannot provide accurate BAC measurement. They will read high, low or correctly and you’ll never know which. If you are close to the legal driving limit of.08BAC, it is quite easy to get readings that vary from.04 BAC to.12 BAC and everywhere in between. The possible marging of error is so wide as to render these devices useless and possibly dangerous if relied upon.

How can I Identify a Semiconductor Breathalyzer?

You can be pretty confident that any personal breathalyzer sold for under $150.00 is a semiconductor device. Most of these products do not identify the technology on the packaging but usually find reference “Semiconductor” in the product specifications.

Are all Breathalyzers to be Avoided?

Professional handheld breathalyzers, such as those used by Law Enforcement do not use semiconductor technology. Professional breath alcohol instruments use “fuel cell technology.” Developed and refined over many years, this technology is more precise, accurate and reliable. Recently, law enforcement manufacturer’s have introduced personal testers that use fuel cell technology.

Why has Nothing Been Done to Remove Semiconductor Alcohol Testers from the Market?

Virtually all semi-conductor breath testers are imported from China, Taiwan or Korea. Many are not approved by the appropriate regulatory authorities before being sold. Those approved are passed as alcohol screeners, meaning they can detect the presence of alcohol but this does not ensure accuracy. No semiconductor alcohol tester has ever been approved for evidential use (to stand-up in a court of law) by any State Law Enforcement Agency or by the U.S. Department of Transportation. The manufacturers are far removed from the hazards of these units, the distributors cover themselves with fine print and the retailers have not stepped up. Buyer beware.