So the meters impedance changes what kind of tests or measurements?
it changes the resistance reading of the circuit or component you're measuring? because of the meter loading? and the meter is in parallel with the circuit?
Additional to my post #2
Voltmeters are put in parallel with the load in order to measure the potential difference between two different points and potential. If they are in parallel with the load, then the first junction the current will split and flow into both paths defined by Kirchhoff's Laws. However, if current is flowing through the voltmeter, then it is not all flowing through the load, and the potential difference across the load would change when the voltmeter is added and removed. Therefore, the voltmeter must have a very high resistance so that current doesn't flow through it. Of course, little amount of current does flow through, but it is insignificant in most cases. Digital voltmeters is better with high impedance, such is case in most pro voltmeters.
If you whant precise measuring you use digital instrument, with analog instruments there is possibility for human factor error. Digital instruments can be very very precise, you see alone what you have in shops, and what people bying, this is not just like that.
As additional comparison:
At digital voltmeters you have digital display with huge digits and with backlight lights, which make easier reading of values, also this eliminate errors durirng readings, what can be situation at analog voltmeter reading of values. Also analog voltmeters are sensitive on shaking and vibrations, like usage in cars, bykes,.... digital dont have nidle and this problems. Because analog have coils they are sensitive to magnets, coils, trafos, they must be far away from this sources, for digital voltmeters that is not the case.
What if engineer have poor vision and use googles (what in case of losing googles), and he is tired after long day, and he should read some value from analog instrument which have thin nidle and small diplay windows? Can you imagine what value will get from reading ?
You can use some nice GLCD and present current measured data on that display like analog instrument with nidle.
Can you imagine analog instrument with nidle in some modern airplane ? Can you tell me why ?
Can you imagine some analog instrument in nuclear plant with stucked nidle on it, and personels reading wrong value, and real value is lots different! About that situation there is one old movie
"The China Syndrome" 1979. Or should I mention "
Three Mile Island accident" from real life. This is excelent example why should go to digital.