How to measure the Burden Voltage of your multimeter

[hgg]

Yes you were right PA4TIM,
The fluke man confused me.  Its clear now.

Thank you!   

[Wytnucls]

The burden voltage varies linearly with the current being measured. The only constant is the shunt resistance for a particular range (Ohm's law). So it should be given as a ratio of voltage versus current, ie: mV/mA. A burden voltage figure by itself doesn't mean anything, unless it is referenced (by convention) to the full current range under consideration.
The burden voltage of the Fluke 87V, for instance, on the milliamp range, is 1.8 mV/mA.

As an example, if your multimeter mA range 5ohm shunt is placed in series to measure the current flowing through a 25ohm circuit powered with a 3V battery, you will measure a current of 100mA instead of the actual 120mA, if the meter was not part of the circuit.

[onlooker]

The burden voltage is not really a voltage. It is always a voltage rate against some current value. The current value may be as sample as 1mA, or something like full scale current of the range in reference.
In the formal case, it is the same as the shunt resistance of the range (in general). 

[Wytnucls]

Well, the effect is referred to as burden voltage, because it robs your circuit of part of the supplied voltage. The lowering of circuit voltage could have consequences for the circuit, especially if the normal operating voltage is only a few volts.

[alm]

But thinking of it as a series resistance is also useful, for example when evaluating the effect on transient response. Good power supplies often specify an output impedance in the order of tens milliOhms up to audio frequencies. Putting 1 ohm in series increases the output impedance by two orders of magnitude. Upping the voltage can compensate for the voltage drop, but not for the poor transient response.