Forums / General help Guidance and Discussion / ADC Doubt - Rickey's World of Microcontrollers & Microprocessors

Discussion in "General help Guidance and Discussion" started by prajwalsnh Dec 7, 2013.

prajwalsnh

[ Fresher ]

Sat Dec 07 2013, 08:21 pm

Hello everyone,

I want to read an analog input voltage of <=5V and convert it to digital data. I want to use AVR as my controller to sample the data. But i have one doubt. The analog input signal has very very less current of order pico amps but voltage level of analog signal will be between 0-5V. Is it possible to digitise the data using inbuilt ADC of AVR? Because the current is extremely low. Due to very low current will the AVR micro accept the input signal or not? Is current a matter for ADC conversion? Pls need help

[ Edited Sat Dec 07 2013, 11:21 pm ]

ajay_bhargav

Site Owner

Mon Dec 16 2013, 03:43 am

Current does not matter for ADC If you can measure the signal with a Multimeter, it can be measured using ADC

prajwalsnh

[ Fresher ]

Mon Dec 16 2013, 11:31 am

@Ajay Bhargav

Thank you sir

ExperimenterUK

Co-Administrator

Tue Dec 17 2013, 12:20 am

A current source in the pico amps range probably will be a problem.
You will need a buffer, such as a fet input op-amp.
What device are you reading ?

prajwalsnh

[ Fresher ]

Tue Dec 17 2013, 10:31 am

@ExperimenterUK

Actually its a research work of my lecturer. He is a PhD holder in physics.. I dont no which device he is reading from. Since he dont know microcontrollers and programming he asked me to digitise the output which is in the range of 5v with very low current of pico amps or even less than that. I thought that such LOW current could be a problem in digitising the data and posted here just to confirm whether its possible or not.