Phil Weasel's Low-Side NMOS Driver Is a Soldering Kit with Real Educational Potential

Maker and educator Phil Weasel has released an open-hardware low-side NMOS driver circuit, designed to teach fundamental concepts at a low cost — making it cheap to replace if students are a little incautious in its handling.

"Cheap to build, easy to assemble, easy to use, much to learn," Weasel writes of his creation. "An incredibly simple circuit for (my) students to learn some fundamental basics and making it a tad more practical. Goal was to make it cheap, easy to replace and handy. Hence the credit card size and very common THT [Through-Hole Technology] parts."

At its simplest, Phil's board can act as a soldering kit — but it's a fully-functional low-side NMOS driver. It includes variable gate-to-source voltage (Vgs), variable gate resistance (Rg), a 5V trigger with BNC connector, the choice of banana plugs or screw terminals for power connections, and test points for probing.

"Possible lessons," Weasel suggests, "can range from: using the oscilloscope; using the function generator; using different measurement tools (shunt, differential probes, current clamp, etc.); measure the MOSFET characteristics (hence the changeable Vgs); charging inductors, driving LEDs/motors, etc.; measur[ing] switching characteristics of the FET (switchable Rg)."

KiCad shematics and PCB files have been published on Hackaday.io under an unspecified open-hardware license.