[Microphones] Mic Hi or Low Z

[George KB2Z]

Good morning all,
I'm new to your list and was hoping you could answer a question.

Is there any way to find if an unknown mic. is high or low impedance? I 
have a few unidentifiable mics that I would like to put into service but 
the impedances are unknown. The actual values are unimportant as long as 
they could be labeled as high or low z.

Thanks in advance, George KB2Z