Our Selection of DMM's (Digital Multimeters)

Number of digits:

This specifies how many digits of a measurement signal can be displayed by a DMM.

Example:

The DMM shown on the left is 4½ digits with 12000 digits. It shows 4 full digits from 0-9 plus one more (here a 1). From a value of 11999 (for example, 11.999 V), the system switches automatically to the next higher measuring range (100 V).

Mean indicating DMM:

For voltage and current measurement, only pure sinusoidal signals are measured correctly. Due to today's requirements, this is no longer up-to-date. Even an electronic low-voltage transformer delivers extremely distorted sinusoidal signals on the output side. With such a DMM you get no or completely wrong values ​​displayed. Therefore, a DMM with TRMS should be used.

Where may the multimeter be used?

Printed in the instruction manual and on the Digital Multimeter (DMM), you will find information on the environment in which it can be used. The maximum permissible stresses in the ranges (measurement categories) must also be taken into account.

• CAT I Measurements on circuits not directly connected to the grid, e.g. Batteries etc.
  
  
• CAT II Measurements on circuits electrically connected directly to the low voltage grid. Via plug, e.g. in the household, office, laboratory ...
  
  
• CAT III Measurements in the building installation. Stationary consumers, distribution connection, devices fixed to the distribution panel.
  
  
• CAT IV Measurements at the source of the low voltage installation. Counter, main connection, primary over-current protection devices.

Three bushings with patented Automatic Bushing Lock (ABS)

All current measuring ranges are routed confusingly over a single socket. The automatic socket lock also prevents incorrect connection of the test leads or the wrong choice of the measured variable. Thus, a risk to the user, the device and the test object due to incorrect operation is largely excluded.
1)  (Patent No. DE 10 2005 062 624, US Pat. No. 7,439,725)