21-11-2012, 12:57 PM
Nick
The RMS value as mention should include the dc component but there are circumstances where the RMS value of the AC component is required, I'm thinking here of ripple voltages on a switch mode supply. My DSO at work has an RMS measurement facility which will include the dc component if the input is set to dc but for these ripple voltage measurements we tend to use the ac setting.
Many of the RMS meters, like the AC ranges on both analogue and digital multimeters, will quote a maximum frequency for measurements.
Mark
You are correct in the definition of the -3db point and I did think about changing it but left it as -3db as most people will have heard of the -3db point.
I did enjoy putting this together and checking out the circuits although like most things a lot was done in the last week before the event. It's very frustrating to have it all prepared and converted to pdf or printed out only to find a small error that once you've spotted it you have to correct it. I find the best way is once I proof read it I leave it for a day or 2 then re-read it and correct all the errors that escaped in the first reading.
In many respects those of us with years of experience are duty bound to pass on our experiences and knowledge to others. I hope this hand out achieves this.
Keith
The RMS value as mention should include the dc component but there are circumstances where the RMS value of the AC component is required, I'm thinking here of ripple voltages on a switch mode supply. My DSO at work has an RMS measurement facility which will include the dc component if the input is set to dc but for these ripple voltage measurements we tend to use the ac setting.
Many of the RMS meters, like the AC ranges on both analogue and digital multimeters, will quote a maximum frequency for measurements.
Mark
You are correct in the definition of the -3db point and I did think about changing it but left it as -3db as most people will have heard of the -3db point.
I did enjoy putting this together and checking out the circuits although like most things a lot was done in the last week before the event. It's very frustrating to have it all prepared and converted to pdf or printed out only to find a small error that once you've spotted it you have to correct it. I find the best way is once I proof read it I leave it for a day or 2 then re-read it and correct all the errors that escaped in the first reading.
In many respects those of us with years of experience are duty bound to pass on our experiences and knowledge to others. I hope this hand out achieves this.
Keith
