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DexterMccoy

Joined Feb 19, 2014
429
Is it true that a compactor ic chip or comparator circuit is jUST a two state output either on or off. The sample and hold circuit is not just off and on states or high and low states
 

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DexterMccoy

Joined Feb 19, 2014
429
The sample and hold circuit must be different because the designer choose it instead of using op amp comparator Circuit. Yes i have seen a fluke meter with the hold button, why?
 

MrChips

Joined Oct 2, 2009
30,824
The HOLD button freezes the reading at the last recorded value.

That is what a sample and hold circuit is supposed to do in your application.
 

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DexterMccoy

Joined Feb 19, 2014
429
The HOLD button freezes the reading at the last recorded value.
That is what a sample and hold circuit is supposed to do in your application.
Yes i know that, but is that what the circuit does that i posted?

The Sine and Cosine is the Reference voltage or the sample voltage? what is the Hold voltage?

I don't know which is the Reference voltage , it is the sine and cosine being compared to what?
 

kubeek

Joined Sep 20, 2005
5,795
It is a differential amplifier, so nothing is being compared, only subtracted.
There is only one input apart from the digital one which controls the switch, so what would you guess is the input that is going to be sampled?
 

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DexterMccoy

Joined Feb 19, 2014
429
so what would you guess is the input that is going to be sampled?
The output of the Op amp gets feedback back to the differential input, this is the sampled voltage right?

It is a differential amplifier, so nothing is being compared, only subtracted.
How is it subtracted? the differential amplifier compares the reference voltage to the sample voltage and subtracts them? at a gain of 1?
 

MrChips

Joined Oct 2, 2009
30,824
A differential amplifier is another name for difference amplifier, i.e. it subtracts two signals.

Guess what a comparator does. It subtracts two signals.
 

Thread Starter

DexterMccoy

Joined Feb 19, 2014
429
Guess what a comparator does. It subtracts two signals.
So what is the difference between a comparator and a sample and hold circuit? they both subtract two signals and output the difference or a differential voltage
 

MrChips

Joined Oct 2, 2009
30,824
A comparator is not a sample and hold circuit.
A sample and hold circuit is not a comparator.
They are two different functions.

You are confusing the function of a circuit and what electronic components are used to implement that function.

It is like asking what is the difference between a filter and a capacitor.
 

Thread Starter

DexterMccoy

Joined Feb 19, 2014
429
A comparator is not a sample and hold circuit.
A sample and hold circuit is not a comparator.
They are two different functions.
I'm not understanding the differences , they are both comparing two signals and subtracting two signals.

So what is the difference?
 
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