Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Video Clips => Topic started by: pompeiisneaks on December 29, 2019, 01:31:32 pm

Title: Signal tracing your amp with a multimeter.
Post by: pompeiisneaks on December 29, 2019, 01:31:32 pm
Figured you guys might know this, but it can't hurt to share :) 
Title: Re: Signal tracing your amp with a multimeter.
Post by: sluckey on December 29, 2019, 02:23:54 pm
In reference to the different voltage readings at the beginning of your video...
Why does the fluke show 150mV and the scope shows 400mV?

It's because the fluke is showing RMS voltage and the scope is showing peak to peak voltage. You need to know the difference and how to convert.

     Vpk = 1.414 x VRMS

     Vpk-to-pk = 2 x 1.414 x VRMS

     In your case, Vpk-to-pk = 2 x 1.414 x 150mVRMS = 424mVpk-to-pk

Maybe your scope is capable of displaying AC sine wave voltage amplitude in RMS value also???
Title: Re: Signal tracing your amp with a multimeter.
Post by: pompeiisneaks on December 29, 2019, 08:13:10 pm
In reference to the different voltage readings at the beginning of your video...
Why does the fluke show 150mV and the scope shows 400mV?

It's because the fluke is showing RMS voltage and the scope is showing peak to peak voltage. You need to know the difference and how to convert.

     Vpk = 1.414 x VRMS

     Vpk-to-pk = 2 x 1.414 x VRMS

     In your case, Vpk-to-pk = 2 x 1.414 x 150mVRMS = 424mVpk-to-pk

Maybe your scope is capable of displaying AC sine wave voltage amplitude in RMS value also???

It probably is, I was just looking at the vernier divisions set at 50mV per division and could count 4 boxes so I knew it was 400mV peak to peak.  There are like multiple different measurements I can select, I may have to take a look at that,

Thanks!

~Phil