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MOSFET switch for LED strips
A logic-level MOSFET (e.g. IRLZ44N) switches LED strips, fans or motors up to 12 V via PWM from a microcontroller. With gate resistor, pull-down and flyback diode; wide traces for the load.
- Size
- 66 × 46 mm, 1.6 mm thick
- Material
- Circuit board (FR4)
- Difficulty
- Intermediate
- Milling time
- approx. 14 min
- Bits
- Engraving bit 30°, PCB drill Ø 0.8 mm, PCB drill Ø 1 mm, PCB drill Ø 1.3 mm, Corn cob router bit Ø 2 mm
- Customise
- Fixed template, freely editable once opened
Free with an account · carve with Chrome or Edge · no installation
Build instructions
Parts
| Qty | Part | Value | In layout |
|---|---|---|---|
| 1 | Resistor 0.25 W | 100 Ω Colour bands: brown, black, brown, gold | R1 |
| 1 | Resistor 0.25 W | 10 kΩ Colour bands: brown, black, orange, gold | R2 |
| 1 | Rectifier diode The band on the case is the cathode and sits on the side of the line in the layout. | 1N4007 | D1 |
| 1 | Logic-level MOSFET Metal tab towards the mark in the layout; screw it down first, then solder. | IRLZ44N | Q1 |
| 3 | Screw terminal 2-pin, 5.08 mm pitch | X1, X2, X3 |
You also need: soldering iron (about 30 W, fine tip), 0.5 to 1 mm solder with flux, side cutters and a multimeter.
Assembly
- Mill the board: isolate the copper first, then drill, and finally mill out the holes and the outline. The order is shown in the Milling panel.
- Cut through the holding tabs, deburr the edges and rub the copper bright with a scouring pad. After that, do not touch the copper side with your fingers.
- Use a magnifier and a continuity tester to look for leftover copper between neighbouring traces; cut any bridges with a craft knife.
- Insert the parts from the side without copper and solder them on the copper side. Fit low parts first: resistors and diodes, then sockets and transistors, and finally capacitors, terminals and large parts.
- Before soldering, compare the polarity with the component layout: band of the diodes, flat side of the LEDs, minus stripe of the electrolytic capacitors, notch of the ICs.
- Solder each lead for about two seconds at around 330 °C: tip on pad and lead, feed solder until it flows all round. Then clip the leads just above the joint.
- Fit the MOSFET Q1 with the metal tab towards the mark. From about 3 A load current, screw it to a heat sink; the tab is connected to drain.
- Fit the flyback diode D1 with the band towards plus. For high currents, reinforce the load traces with solder.
- Visual check: no solder bridges, no dull, balled-up joints. Remove flux residue with isopropyl alcohol and an old toothbrush.
Test and power up
- Before switching on for the first time, check with the meter that there is no short between plus and minus of the supply. Power up the first time on a bench supply with current limiting if possible.
- Apply 12 V to X3 and connect the load (e.g. an LED strip) to X2 with plus to +.
- Connect the microcontroller's PWM pin to X1: at HIGH the strip lights fully, with PWM it can be dimmed. Without a signal, R2 keeps the MOSFET safely off.
- Finally protect the copper side against oxidation with solder lacquer or plastic spray.
How to carve this template
- OpenOpen the template in the app and adjust size and text if you like.
- CheckLook at it in 3D, check run time and warnings.
- Set upThe carve wizard guides you through material, clamping, bit and zero point.
- CarvePress start; the app drives your Grbl router directly over USB.
