Dear friends,
I've developed an electronic design in which I've included a current sensor. The input current range is 4mA  20mA. To measure this current I've designed the simply system depicted in the image attached (Capture.JPG), based on a resistance of 250ohm connected to ground, so a (4mA, 20mA) corresponds to (1V, 5V) range, which is registered in one ADC channel of an Arduino.
The question is I've solder a 250 ohm SMD 0603 resistance with this characteristic:
 Max dissipation @ Tamb=70ºC  1/10W (0.1W)
If the input current is the maximum in my range (20mA), the dissipated power in the resistance will be 0.1W. Notice that Tamb in my system will be rooom temperature aprox.
The point is that I'm not sure if this margin is a poor margin and consequently I've a mistake in my design (the resistance is already soldered to the pcb...).
Do you think this design is OK or I shoud resolder another kind of resistance?
Thanks!
I've developed an electronic design in which I've included a current sensor. The input current range is 4mA  20mA. To measure this current I've designed the simply system depicted in the image attached (Capture.JPG), based on a resistance of 250ohm connected to ground, so a (4mA, 20mA) corresponds to (1V, 5V) range, which is registered in one ADC channel of an Arduino.
The question is I've solder a 250 ohm SMD 0603 resistance with this characteristic:
 Max dissipation @ Tamb=70ºC  1/10W (0.1W)
If the input current is the maximum in my range (20mA), the dissipated power in the resistance will be 0.1W. Notice that Tamb in my system will be rooom temperature aprox.
The point is that I'm not sure if this margin is a poor margin and consequently I've a mistake in my design (the resistance is already soldered to the pcb...).
Do you think this design is OK or I shoud resolder another kind of resistance?
Thanks!
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