Hi all,
I'm trying to measure and log the short-circuit current I_sc of a single solar cell (0.5V-6A) with an Arduino and am having trouble with the setup of the circuit. I'm a beginner with electronics, please take this into account.
Basically this is where I am at:
-I understood that the best way to measure current is to measure voltage drop over a shunt resistance, which is a very small resistance, getting close enough to a short-circuit but still imposing some resistance over which we can measure a voltage drop. This voltage drop, with Ohm's law, gives us I_sc.
-In order to be able to read this small voltage drop, an amplifier must be used. One possibility seems to be the INA219 module. This comes with an internal shunt resistance of 0.1 Ohm. I thought this would make the job easier because I wouldn't need to add a shunt resistance myself. However, I was told that this resistance is way too high for my application. Is this because my voltage is so low to the voltage drop would be too significant? Should I mount an external (smaller) shunt resistance and if yes how?
-In order for the cell not to burn down due to being shorted for a prolonged time, a MOSFET transistor can be used to short the circuit only during the time necessary for the measurement.
My doubts, on top of the bold question within the above paragraph:
- Is this a correct (and the most simple) way to measure short-circuit current with an Arduino?
- Don't the internal resistances of the MOSFET and the solar cell influence the measurements of the short-circuit current?
- If I do need to change the shunt resistance of the module, how can I calculate how large (or how small) this shunt resistance should be?
I'm quite confused here... Simple terms would greatly help me because as said, I have very limited experience with electronics (and probably don't even fully understand the concepts which I described above yet).
Thanks a lot!
I'm trying to measure and log the short-circuit current I_sc of a single solar cell (0.5V-6A) with an Arduino and am having trouble with the setup of the circuit. I'm a beginner with electronics, please take this into account.
Basically this is where I am at:
-I understood that the best way to measure current is to measure voltage drop over a shunt resistance, which is a very small resistance, getting close enough to a short-circuit but still imposing some resistance over which we can measure a voltage drop. This voltage drop, with Ohm's law, gives us I_sc.
-In order to be able to read this small voltage drop, an amplifier must be used. One possibility seems to be the INA219 module. This comes with an internal shunt resistance of 0.1 Ohm. I thought this would make the job easier because I wouldn't need to add a shunt resistance myself. However, I was told that this resistance is way too high for my application. Is this because my voltage is so low to the voltage drop would be too significant? Should I mount an external (smaller) shunt resistance and if yes how?
-In order for the cell not to burn down due to being shorted for a prolonged time, a MOSFET transistor can be used to short the circuit only during the time necessary for the measurement.
My doubts, on top of the bold question within the above paragraph:
- Is this a correct (and the most simple) way to measure short-circuit current with an Arduino?
- Don't the internal resistances of the MOSFET and the solar cell influence the measurements of the short-circuit current?
- If I do need to change the shunt resistance of the module, how can I calculate how large (or how small) this shunt resistance should be?
I'm quite confused here... Simple terms would greatly help me because as said, I have very limited experience with electronics (and probably don't even fully understand the concepts which I described above yet).
Thanks a lot!