Battery-powered DMMs (digital multi-meters) have been around for years, but they're usually in handheld cases. Sometimes, though, you need the power of a bench DMM to use in places where AC mains power isn't available. That's where the Model 1908 from Aim-TTi (Aim-Thurlby Thandar Instruments) comes in.

[1908P AimTTi cr] *__Figure 1:__ The battery-powered Model 1908 can store up to 500 readings sampled at 1 reading/sec to 1 reading every 3 hours.*

The bench-form-factor Model 1908 includes rechargeable batteries that, according to the company, can keep the meter powered for 35 hours. Whether running on battery or AC mains power, the Model 1908 has a dual display so you can see both voltage and current (or other measurements) at the same time. Besides measuring AC (true rms) and DC voltage and current, the instrument measures resistance (two or four wire), frequency, capacitance, and temperature (Pt100 or Pt1000 RTD). Math functions include min/max, power in Watts or VA, Ax+B, limits, per cent deviation, and readings in dB.

Because the Model 1908 is battery powered, you expect it to have datalogging capability. It can store up to 500 readings sampled at 1 reading/sec to 1 reading every 3 hours. You can manually recall the readings or store them in CSV format for transfer to a PC. Software support includes IVI drivers, LabVIEW and LabWindows/CVI, and USB. A Windows-based software app lets you store and plot data. For automated-test applications, the Model 1908 has an external trigger input and an isolated open-collector output for driving an indicator or relay.

The 1908 model with USB interface is priced at about $667, while Model 1908P (USB, LAN, GPIB and RS-232 interface) come for about $756.

This article was first published by EDN.