I would like to measure both voltage and current using a PIC. I have been doing some research and found that the PIC would be most happy if it has a high impedance input into the ADC and this can be accomplished with an OP AMP.
I read a bit about op amps in the wonderful tutorials on this site but these little devices do so many things, I am not sure exactly what I need to accomplish my task.
Can any one point me to a sample circuit that I can measure voltage in the range of 0-30 VDC and current maybe a 1ma or so to maybe 1 or 2 amps? My supply to the PIC will be 5VDC so therefore my reference voltage for the ADC will be 5VDC.
I would like to power the op amp with the same 5 VDC. I don't want to have to add any extra supply voltages.
I know I can use a voltage divider using resistors but that is about as far as I know to read the voltage from the ADC. I would like to be able to do it with an op amp.
Plus points for being able to turn the op amps on and off so that I can read multiple sources with the same ADC input.
I read a bit about op amps in the wonderful tutorials on this site but these little devices do so many things, I am not sure exactly what I need to accomplish my task.
Can any one point me to a sample circuit that I can measure voltage in the range of 0-30 VDC and current maybe a 1ma or so to maybe 1 or 2 amps? My supply to the PIC will be 5VDC so therefore my reference voltage for the ADC will be 5VDC.
I would like to power the op amp with the same 5 VDC. I don't want to have to add any extra supply voltages.
I know I can use a voltage divider using resistors but that is about as far as I know to read the voltage from the ADC. I would like to be able to do it with an op amp.
Plus points for being able to turn the op amps on and off so that I can read multiple sources with the same ADC input.