Thank you for explaining why TH resistors are God-forsaken dark blue - to obtain higher emissivity, lol. I'd say it's a half-space on a pc board.
I note the
SFR25H 0.5W is dark red-brown body vs SFR25 light green, 0.4W I guess it's the dark lacquer giving 25% more? Usually it's due to a change from steel to copper leads.
But the smaller SFR16S isn't the darker lacquer, has thinner leads- which is why I smell a rat.
I find OP got burned because resistor manufacturers are specifying power rating P
70 at different film temperatures. Considering the parts have 100 years of history, and their standards are European, Asian, American with different material tech, it's not a standard it seems.
Same size MELF
SSM0204 is given three different "operation modes": precision 0.07W, standard 0.25W, power 0.4W, all for the same part.
This is very important here, especially noobs that don't know how much or when to derate film resistors, and that their
rated power is specified at any one of those three modes, and for different temperatures. Digi-Key parameter for the part is 0.25W which is the standard mode, OP's fake SFH16S is 0.5W power mode (no other manufacturer is doing this for a similar part) and surely a typo anyway, as if it's 0.5W at 155°C beating the larger parts.
Other manufacturers are using standard mode on their datasheets, unless precision parts. Some are 55-85°C at their spec. So the datasheets are all over the place.
I'm avoiding going into haggling over thermodynamics here in a Beginner's thread.
Thermal Management in Surface-Mounted Resistor Applications is a good read. They're using an infinite heatsink.
edit: forgot clip