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why Fluke use bandpass filter in their DMMs?

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MegaVolt:

--- Quote from: David Hess on October 04, 2023, 09:11:55 pm ---There is a similar configuration for a DC accurate precision rectifier which is AC coupled on its input and output.

--- End quote ---
Do you have an example circuit diagram?

tridac:
Been trying to find more info on this filter design. Asked in another thread and pointed towards a Burr Brown third gen op amp techniques book, since found on ABE books. Still interested in a more thorough treatment, so which book or source did you find the above 5th order example ?.

Thanks, still collecting data...

MegaVolt:

--- Quote from: tridac on October 05, 2023, 12:15:09 pm ---Still interested in a more thorough treatment, so which book or source did you find the above 5th order example ?

--- End quote ---

David Hess:

--- Quote from: MegaVolt on October 05, 2023, 10:19:40 am ---
--- Quote from: David Hess on October 04, 2023, 09:11:55 pm ---There is a similar configuration for a DC accurate precision rectifier which is AC coupled on its input and output.

--- End quote ---
Do you have an example circuit diagram?
--- End quote ---

The Tektronix DM501 and DM502 use it with a 318 type of operational amplifier which otherwise would contribute large DC errors.

tszaboo:

--- Quote from: Kleinstein on October 05, 2023, 07:48:25 am ---In a few cases light bulbs are used as a low current fuse.
In the plan from the start the circle with x symbol is not for light bulbs but for CMOS switches.  So no light bulbs but chip internal CMOS switches for the signal.

P.s. : A light bulb is not a good fuse and may fail with an arc flash. It is not uncommon for a failing mains bulb to take out the breaker from that.

--- End quote ---


--- Quote from: David Hess on October 05, 2023, 07:08:56 am ---
--- Quote from: tszaboo on October 04, 2023, 10:36:32 pm ---Why do they have so many lightbulbs in a multimeter?
--- End quote ---

As shown below, what light bulbs in multimeters might look like.


--- End quote ---

Come on, take a look at the picture, there are at least 20 light bulbs in that multimeter according to the schematic.
Or someone used that symbol as the selector switch's switching part as a lightbulb. If you look at it, 29-30-31-32 clearly sets a gain of an amplifier.

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