Air Ion Counter Specifications
Air flow: 400 cc/sec. Linear speed is 80 cm/sec through a polarization field of 2500 V/m and the system is designed to collect 60% of the ions in still air at this speed. A lower percentage is collected if air is forced faster than 80 cm/sec through the inlet slot, and a higher percentage than 60% is collected if a reverse air flow slows the air flow. This maintains the accuracy in windy conditions. It is within specified accuracy for air flow from 200 to 800 cc/sec.
Dynamic Range: For the standard "2 million" version, 10 - 1,999,000 ions/cc, both selectively "+" and selectively "-". For the "20 million" version, range is 100 - 19,990,000 ions/cc. For "200 million", it is 1000 - 199,900,000 ions/cc.
Setting time: Approx. 1 second (response time), and 10 sec (after switchover between "+" and "-")
Noise level: (2 second-weighting) approximately 10 ions/cm3
Input resistance: 1010 Ohms.
Accuracy: +/-25% for fast ions (mobility greater than 8 x 10-5 m/s per V/m - these are the most numerous ions. The Air Ion Counter is less sensitive to "slow" ions such as charged pieces of dust). Stays within 25% for air speeds up to 15 km/hr in any direction. Temperature range is -10 to +50C (14 to 122F). Humidity: up to 90% (condensing).
Battery: One 9V alkaline. Current drain is about 5ma on STANDBY, and 40ma on MEASURE. All 3 decimal points display when battery becomes weak (below 7.4V). Battery life is about 40 hours on STANDBY and 2-3 hours on MEASURE. If ordered with the Li-ion battery option, running time until low battery indicator is about 60 hours on STANDBY and 6 hours on MEASURE. Li-ion recharge time is 3 hours, but the charger can remain plugged in indefinitely and the charger will power the Air Ion Counter. Li-ion battery life is 5 years or 500 charge cycles, and is replaceable.
Ion Selectivity (crosstalk): 1:5000. That is, if POLARITY is set to "+", the meter will display 1/5000 of the "-" ion density (as a negative number) if there are many negative ions and no positive ions. With POLARITY set in its center position, the meter will read a number which is 1/10 the "+" density, minus 1/10 the "-" density.
Output (option): Output is analog; +/- 1.999 volt corresponds to full scale on all ranges. For example, if the standard "2 million" range meter is configured with an output, a reading of "-150.0" on the 199.9 range will produce an output of -1.5 volts which corresponds to 150,000 ions/cc. With the output option, there is no "RE-ZERO" switch. Instead, a single rotary control (knob) is set once so that the display reads zero when no ions are present. There is a small change in offset with temperature of about 10 ions/cc per degree C. If the temperature remains the same or if it changes but then returns to the original temperature, the rotary control will not need to be changed to a new setting. An AC adaptor comes with the output option; when the adaptor is plugged into the meter, the alkaline battery will be "disconnected", and is not recharged. (If the Li-ion rechargeable battery option is ordered, disregard the previous sentence.)
Warranty: 1 year
Manufactured in USA from international components. Circuit board was made in USA. Its assembly and all machining and calibration were done by AlphaLab in Salt Lake City.