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+--- Thread: 1/2W or 1/4W for the resistors on the Pypilot board? (/showthread.php?tid=5702)
1/2W or 1/4W for the resistors on the Pypilot board? - volksbar - 2024-09-14
Hello,
I am a newbie, trying to assemble the Pypilot myself, following Andreas's plan (https://github.com/AndreasW29/pypilot-tinypilot-mysolution-infos).
I am wondering if 1/4W is enough for the resistors on the Pypilot board (ranging from 430 Ω to 120 kΩ). It is not specified in his documentation of the parts. Many thanks!
RE: 1/2W or 1/4W for the resistors on the Pypilot board? - ironman - 2024-09-15
1/8 Watt for most of them, except for the current sense (R20) and the arduino power one (R1), that should be a bit more.
See this link for the pertaining schematic, and this link for the earlier discussion.
RE: 1/2W or 1/4W for the resistors on the Pypilot board? - seandepagnier - 2024-09-15
You can take the voltage (in this case 5v or 3v3) and use the formula: V^2/R to determine wattage.
Generally these resistors see less than the full 5 volts, but you can see a 100 ohm resistor at 5 volts dissipates 1/4th watt. I then try to at least double this, so the 100 ohm resistor might be 1/2 watt, but it would only see this if the output of the regulator is shorted.
So basically every resistor at be 1/8th or 1/10th watt, except the current sensor or arduino power. My newer designs dont use the arduino power resistor but instead regulate current to limit it in case of a short.