I am fairly inexperienced with electronics so please bear with me.
I have an Arduino Nano 33 IoT being powered by a battery pack which at 100% outputs 40.2V and at 0% outputs 36.5V Since the Max Vin Voltage the Arduino supports is 21V, I am using a LM2596 to reduce the input voltage from the battery(40V) to the Arduino(10V)
When I was testing the LM2596 I noticed some sparks came out, then when I started searching about it I figured it out that is was inrush current probably caused by the capacitors being charged? Correct me if I am wrong. Then I searched on how could I prevent my circuit from frying up, and couple solutions came up with resistors or NTCs. But the main issue now is, which resistor to chose from(Ohm wise)? or the NTC Thermistor? What's the math and the calculations behind it?
Thanks in advance!