# Circuit diagram for 12 bit ADC with Microcontroller

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#### popat_panjaru

##### Full Member level 2

hi to all

my requirement is of Circuit diagram for 12 bit ADC with Microcontroller...if anybody has plz send it to me....

basically PIC type controller circuit diagram is required...

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#### A.Anand Srinivasan

what type of ADC are you planning to build....

### popat_panjaru

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#### popat_panjaru

##### Full Member level 2
analog to digital converter circuit diagram

i m going to build Successive approxiation type...

or if any other which is regularly use by Market

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#### A.Anand Srinivasan

i tried a similar circuit.... what PIC are you using.... the circuit just needs a comparator and a DAC kit that is all... all other things are done using coding....

### popat_panjaru

Points: 2

#### popat_panjaru

##### Full Member level 2
circuit diagram of a microcontroller

i m using 18f series PIC...

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#### A.Anand Srinivasan

microcontroller schematic diagram

it is hard to draw the circuit and post(i'm lazzzzzy ).... i give the general idea first set MSB to 1 and send it to DAC and compare it with the analog signal using the comparator and if analog signal is high then set the MSB else reset it now let the MSB untouched and set the next MSB and repeat the process.....

as you can see the circuit outside the microC involves just a DAC and a comparator and some wires....

### popat_panjaru

Points: 2

#### popat_panjaru

##### Full Member level 2

yaar,

plz try to send me...because i can not get ur point...

its look like we are talking in air...

plzzzzzzzzzzzzzzzzzzzz do it for me....

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#### popat_panjaru

##### Full Member level 2

how can we set the sampling rate?...

is there any equation or theory based on?..

Plz send me if any body has..............

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#### A.Anand Srinivasan

the sampling rate is determined by the speed of your microcontroller.... your sampling rate should be such that the next sample is taken after the first sample is fully converted to its digital value.....

the circuit i'm suggesting is

#### popat_panjaru

##### Full Member level 2

so how that value can be counted?...

is there any kind of eqution that will be used for?..

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#### A.Anand Srinivasan

circuit diagram for 12 bit adc

the counting algorithm you are supposed to write in the microcontroller....

#### popat_panjaru

##### Full Member level 2
circuit diagram of 12 bit adc

can u explain it to me with one short and sweet example?...

i have never made any kind of counting algorithm?..

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#### A.Anand Srinivasan

first set the MSB bit to 1 and all other bits to 0 and convert it to analog and compare it with the input
if input is larger then retain that one else rotate and reset the MSB.... now set the next MSB and check and if greater leave it else reset that bit... continue this way till the LSB... the rotation part is critical....

#### Kurenai_ryu

circuit diagram for 12- bit adc

also... dont mind, but...

how can you implement a sample&hold??? its very important so you can measure higher frecuencies...

(if you change the analog signal while its measuring by successive aprox. the result wouldn't be accurated...)
(the sampling rate, will be the 12 times the bit shifting plus init, plus the sample&hold...)
(your DAC should be of 12bits or more.... a high precisition comparator [also fast] so much work... maybe its easier to go and find a ADC of 12 bits...)

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