[time-nuts] Newbie questions

Artek Manuals Manuals at ArtekManuals.com
Wed Jan 27 19:39:12 UTC 2016

You will find the following discussion of dB useful


dB references are not just for RF it  is/was used extensively in audio 
work as well where it was often related to 600ohm load vs the 50ohm RF load

As for DMM I have a Tektronix DM501A and a DM502A both have dB scales. I 
have a 20+ year old Radio-Schlock DMM which also has a Db scale. Then 
there are all the analog HP 4xx series all of which have dB scales 
regardless of frequency coverage AC volt meters, RF power meters etc. 
Also the Boonton 92 series all incorporate dBm scales ...and the list 
goes on

Have fun and welcome back to the world of practical electronics 


On 1/27/2016 12:41 PM, timenut at metachaos.net wrote:
> Bill,
> Thanks. Your reply was very informative. I understand the reason for using
> decibels for the applications you mention. However, I did not consider the
> output level of a non-RF signal to be in that category.
> You are right, I have never seen a DMM reading in decimals. I know that
> digital scopes can do so (and understand how they work), but again I have
> never seen or used one. Given the zero point (finally figured that one out, I
> was missing the assumed impedance factor which was varying) I can convert
> levels - not quite in my head, since I can't do logs in my head - but close
> and can get a pretty good guestimate that way.

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