I have a soft PCB with a tiny switch on top of which I want to add another switch (a mosfet).
What would be a good practice to do so? Just solder threads (hypothetical, in blue in the picture) connecting the mosfet of something else?
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- 1\$\begingroup\$ Measure whether one of two pins is Gnd or Vcc with ohmmeter. According this you select mosfet type (N-ch/P-ch). \$\endgroup\$Michal Podmanický– Michal Podmanický2025-11-03 17:36:54 +00:00Commented Nov 3 at 17:36
- \$\begingroup\$ @MichalPodmanický Indeed that's something that needs to be determined ! One may think that making the connection is enough, but no. \$\endgroup\$Soleil– Soleil2025-11-03 19:24:38 +00:00Commented Nov 3 at 19:24
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2 Yes, that is a very common method of doing what you intend. IPC guidelines encourage you to avoid routing the wires over or under other components or over other solder lands. Staking the wire is also a good idea, though not strictly required.
The required solder fillet coverage is 100% of the distance from the edge of the land to the knee of the lead unless you have 3 wire diameters (including insulation) of overlap which I kind of doubt you will be able to achieve. The jumper wire should not extend past the knee of the lead. If you trim the jumper wire back to the knee of the lead after soldering, you must reflow the joint.
I assume you have verified that the MOSFET you intend to use is compatible with the application wrt type (P-ch/N-ch) and polarity.
- \$\begingroup\$ Thanks. I am not sure that it is, I picked an N mosfet. I will post another question on that topic. \$\endgroup\$Soleil– Soleil2025-11-03 19:26:53 +00:00Commented Nov 3 at 19:26
- \$\begingroup\$ This is the follow-up question: electronics.stackexchange.com/questions/760174/… \$\endgroup\$Soleil– Soleil2025-11-03 20:07:24 +00:00Commented Nov 3 at 20:07