Free online calculator
Example Heatsink must be 18 °C/W or better — the sink then sits at 115 °C and the case at 117.5 °C (total budget 20 °C/W)
— the heatsink only gets what is left of the budget after the package and the interface have taken theirs.
What you enter
AWG ↔ mm²The gauge is geometric, not a lookup table: mm, and . Resistance assumes copper at 20 °C.
Controlled impedanceA trace over a single reference plane, solved backwards from IPC-2141's own closed-form approximation: . Good to a few percent for 0.1 ≤ w/h ≤ 2 — the…
PCB trace ampacityEmpirical IPC-2221 formula — a design estimate, not a manufacturer guarantee.
Wire voltage drop, where for a round trip. The ohms per metre come from the AWG table.
LC resonanceAt that frequency the two reactances are equal — — and the branch currents cancel, so this parallel tank presents its highest impedance.
LED series resistorNobody wires just one LED. Each string is its own series chain of LEDs behind its own resistor — stringing more LEDs raises the headroom the resistor has…
MOSFET gate driveA MOSFET draws no steady gate current, so holding it on is free — but every edge has to shovel the whole gate charge in and back out again, and is real…
NE555 timerFully wired timing network — pins are grouped by function, not physical DIP order (see the 555 timer entry in Pinouts for the real pin layout). RST is…