In Focus: Electronic Specialties 688 True RMS Low Current Clamp Meter

The Electronic Specialties True RMS Low Current Clamp Meter, No. 688, features a 3/4" clamp opening, which allows clamping over heavy duty ground cables and some multiple ground cable systems. The larger clamp will permit a wider range of use across heavy duty vehicles. This clamp meter has improved the drift on DC amps readings, and it has a built-in full range digital multimeter for true RMS accuracy. The clamp meter measures DC/AC volts, ohms, frequency, capacitance, diodes, continuity and temperature in Fahrenheit and Celsius. Multimeter test leads, temperature probe and zippered carrying case are included.

Selling points

  • Measures down to 1 mA accurately, for measuring and diagnosing parasitic battery drains.
  • Large clamp size of 0.75” (19mm) clamps over larger heavy duty ground cables and some multiple ground cable systems.
  • Much improved zero-stability allows higher confidence in low current readings.
  • Full-function DMM is built into the 688, including temperature readings.

Features and benefits

The 688 is geared to help technicians deal with battery drains effectively and help locate the drain quickly. It all starts by clamping over the negative battery cable to read the residual currents in the system. From there, the technician can pull fuses to see which circuit is drawing the amps. The 688 also measures up to 80 amps, so there are many applications, such as verifying correct charging current in DC to DC converters on hybrids.


The 688 can perform all types of electrical troubleshooting, from voltage and resistance issues to problems in which amperage readings are key to the diagnosis. Most importantly, this unit is geared to address the challenges of taking accurate low-current readings when battery drains persist.


The idea was derived completely from customer feedback. Users and dealers have been giving feedback on the earlier model low-current probe. The company took that feedback and designed a completely new clamp meter, which incorporates those requests.

One issue has been the clamp size. Clamping over the negative battery cable speeds up the diagnosis of battery drains. Our prior model could not clamp over some larger cables and some multiple cable systems. The 688 can now clamp over those and provide the readings needed to diagnose and locate the problem.

Manufacturing specs

The 688 measures currents from 1mA up to 80 amps. It also measures DC and AC voltage, ohms, frequency (Hz) capacitance, diodes, temperature and continuity. Other notable specifications include min/max, peak min/max, analog bargraph and a backlit 5,000-count LCD display. A zippered carrying case comes included.

Storage and display

The unit is packed in a full-color box suitable for display anywhere on the truck.





Suggested retail price


For more information

(800) 227-1603

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