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How to fit a hot NTC between components?


Advanced Member level 5
Jun 13, 2021
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We have a space constrained 20W offline Flyback with a 47R NTC (SCK10472MSY). The NTC is in the input line (AC section)
The NTC is in a gap between the metal enclosure and the input X2 capacitor. The NTC is 1.7mm away from the X2 capacitor and 0.2mm away from the earthed metal enclosure.
We can put Kapton over the earthed metal enclosure as it abutts the NTC. But what would you say is best to put in the 1.7mm gap between the NTC and the X2 capacitor? The NTC obviously gets very hot, and so we cant risk it touching against the plastic X2 capacitor case.

Also, are there any tall thin NTCs so we can increase spacing like that?...because we have some 4.5cm of free space going vertically.
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..What we actually need is like a thin sheet of nonflammable plastic on two pins, so we can solder it in and have it between the NTC and the capacitor....separating them.
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..even wondering about having a "dud" TO220 diode (say) in there to act as the separator (not part of any circuit)
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..or just dunking a 15mm x 15mm by 0.5mm thick sqare of plastic between the NTC and the capacitor, and "gunging" it down to the PCB with some silicon?
put two layers of heatshrink over the NTC / inrush limiter - this will keep it nice and hot ( low Ron ) during operation - but not cook the nearby components, also allow tall legs so the heat doesn't get into the pcb and ruin the solder joints.

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