The DO4A is a practical instrument for low resistance measurement, ideal for use in the workshop, field or test facilities.

It is of rugged construction contained in an aluminium case with tilt handle. The DO4A has many advanced features, including protection up to 415 volts rms, digital calibration and long scale length (4000 count). The rechargeable sealed lead acid battery means real portability with more than 14 hours continuous operation, without the problems normally associated with other battery types. Full measurement capability is maintained while charging.

For ease of operation the control functions have been kept to a minimum and are clearly marked. It is of course direct reading, warning LEDs illuminate when an open circuit lead condition is detected. Over range and low battery indication is also provided. The DO4A is supplied ready for immediate use with battery, mains cord and measuring leads, no extras are normally necessary.

The 15mm LCD provides easy viewing and the instrument can be used in any position for many and varied applications.

The test leads provided have a length of 1 metre with spade tags for connection to the ohmmeter terminals. They are terminated in combined current and potential probes that will accept conductor diameters up to 0.24in.

Data Sheet

Key Features

  10 micro ohm resolution on 40 milli ohm range
  Input protection up to 415 Volts rms
  Zero control thermal E.M.F. compensation
  Digital calibration
  Mains / rechargeable battery operation
  Open circuit lead warning
  Rugged industrial maintenance free design
  True 4 wire measurement eliminates lead resistance errors
  6 push button ranges 40 milli ohm… 4 kilo ohmwith long scale length
  Universal mains supply 100 / 200 / 220/ 240 Volts +10% - 13%

Measurement

4 terminal Kelvin/Thomson principle eliminates errors due to lead resistance

Display

0.6in LCD 4000 count with automatic decimal point and polarity indication

Ranges

6 push button selected with LED indication

Terminals

0.2in binding posts accept spade tags and 4mm banana plugs

Working Temperature

0°C to +40°C re. humidity 80% max. non-condensing

Storage Temperature

-20°C to +50°C

Mains Supply

100/120/220/240V +10% to 13%
47Hz to 63Hz 20VA

Safety

EN 61010-1 EMC-EN 61236

Dimensions

8.5in x 9.8mm x 0.3in (W H D) approx
1/2 19” rack 2U high
1.5ft x 14.73in x 8.5in packed in carton

Mass

7.7lbs approx. 9.9lbs packed in carton

Auto Zero

Permits the automatic zero of amplifiers and external circuits, eliminating errors due to thermal E.M.F.

Protection

415 Vrms maximum at the measuring terminals will blow internal protection fuse

Calibration

Digital security key protected

Battery

6V 2.8Ah sealed lead acid battery with built-in charger. 14 hour typical operating time on lowest range, 28 hours typical on other rages. Internal charger and automatic switch off