Good evening,
I would like to measure the voltage delivered by a photovoltaic panel whose characteristic parameters are as follows:
Isc = 5.92 A
Voc = 44.5V
Imppt = 5.48 A
Vmppt = 36.5V.
I need to lower the voltage from 44.5 to 5V to be able to measure it by Arduino using the voltage divider bridge.
If for example I use a total resistance of 10kΩ which will give R1 = 9kΩ, R2 = 1kΩ and I = 4.45 mA and the powers dissipated by the two resistors are: P1 = 0.175 W and P2 = 0.022 W.
but if I go for a total resistance of 40k I will have: I = 1.1mA, R1 = 36kΩ, R2 = 4kΩ, P1 = 0.044 W, P2 = 0.0055 W.
I know that whatever resistors are chosen, the important thing is that I must not exceed the nominal power of the resistor, but both cases give me currents I = 4.45 mA and I = 1.1 mA. My question is on what criteria I will use to choose the right amperage, is it better to choose the smallest or the largest amperage?
Thank you
I would like to measure the voltage delivered by a photovoltaic panel whose characteristic parameters are as follows:
Isc = 5.92 A
Voc = 44.5V
Imppt = 5.48 A
Vmppt = 36.5V.
I need to lower the voltage from 44.5 to 5V to be able to measure it by Arduino using the voltage divider bridge.
If for example I use a total resistance of 10kΩ which will give R1 = 9kΩ, R2 = 1kΩ and I = 4.45 mA and the powers dissipated by the two resistors are: P1 = 0.175 W and P2 = 0.022 W.
but if I go for a total resistance of 40k I will have: I = 1.1mA, R1 = 36kΩ, R2 = 4kΩ, P1 = 0.044 W, P2 = 0.0055 W.
I know that whatever resistors are chosen, the important thing is that I must not exceed the nominal power of the resistor, but both cases give me currents I = 4.45 mA and I = 1.1 mA. My question is on what criteria I will use to choose the right amperage, is it better to choose the smallest or the largest amperage?
Thank you