Jump to content
Electronics-Lab.com Community

True RMS

Kevin Weddle

Recommended Posts

Hi Kevin,
Check the frequency response of your meter with sine-waves on each voltage range of it. You will probably find that the response drops-off above only a few hundred Hz, especially at high voltage ranges.
The frequency response of my premium true-RMS-reading DMM is down 3dB (0.707 of the correct voltage) at 17Hz and 17KHz. My cheap DMM is down 3dB at 58KHz and perfect at 10Hz (my lowest frequency). The lowest range on my good meter is 400mV and is 200V on my cheap one which explains the difference in frequency response between them.

Therefore you should use an oscilloscope to measure the level of clock signals if they are at a high frequency.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...