# Current & voltage control for ADC input

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#### fireball003

##### Full Member level 3 Hi,
My microcontroller ADC can take input from 0-5 volt. But my input voltage is much more than that. Same for Direct current. Which circuit will help me to reduce the voltage using a known equation ? (So that I can calculate and get the original voltage and current value while computing inside microcontroller.)

Is Op-amp helpful here? Then what would be the circuit?

Thanks a lot

#### Sudhir.K.A

##### Member level 2 Hi fireball003,
Why don't you go for a simple resistor divider circuit.
I think this will be the first option you have to try.

If any condition like high output impedance is there,
then we can tackle that by using a buffer.

It is better to know the scenario under which attenuation has to be done for better answer.

regards,
sudhir

Hi fireball003,
Why don't you go for a simple resistor divider circuit.
I think this will be the first option you have to try.

If any condition like high output impedance is there,
then we can tackle that by using a buffer.

It is better to know the scenario under which attenuation has to be done for better answer.

regards,
sudhir

#### fireball003

##### Full Member level 3 Hi sudhir,

I am trying to measure voltage and current continuously. To be precise I am trying to build a system- microcontroller based voltage and current measurement system where I don’t have the voltage or current limit. May be it is too large. So, I was thinking of a system that will follow a known equation.

Theoretically the domain of the equation will be up to infinity. And the range of the equation will be from 0 to 5. So that it’s output will be 0 to 5. Later I will recover the original value by calculating inside microcontroller. How would I do that using analog circuit?

I think I thought of that system in much more complicated way. Suggestions are also very much welcome.

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