ElectroLab AIVisual build guides
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Intermediate

PWM Motor Controller

Build a low-side MOSFET controller where a timer makes PWM and the motor current stays off the breadboard.

Safety first, always.

ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.

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PWM Motor ControllerA timer creates the speed signal; a MOSFET switches motor current with flyback protection and local capacitance.+groundmotor +motor -diode stripePWMgatesupply capDC IN6-12 VFUSEmotorPWM555/moduleGATER + pulldownMOSFETlow sideMOTORbrushed DCFLYBACKdiodeDo not run motor current through a breadboard. Use small low-voltage brushed motors only.

Motor control build

Build a low-voltage PWM speed controller with a MOSFET, flyback diode, and proper motor current path.

Bench time

2-4 hours

Typical parts

$20-$55 AUD

Power

6-12 V DC current-limited supply

You finish with

Variable-speed DC motor controller

Before the first wire

Know the build before you power it.

Use a small brushed DC motor first, not a high-current automotive motor.

The motor current path must not run through a breadboard.

Fit a flyback diode or suppression network across the motor.

Use a logic-level MOSFET that fully turns on from the timer/controller voltage.

Bill of materials

7 parts groups to gather

Check every spec

QtyPartExact specWhat it doesInspect before use
1555 PWM board or controllerAdjustable duty outputCreates the speed command.Output voltage suits MOSFET gate drive.
1Logic-level N-MOSFETCurrent rating above motor stall currentSwitches motor current.Identify gate, drain, and source correctly.
1Flyback diodeSchottky or fast diode rated above motor currentCatches inductive kick.Stripe faces motor positive for low-side switching.
1Gate resistor47-220 ohmTames gate ringing.Fitted close to MOSFET gate.
1Gate pulldown47-100 kohmKeeps motor off at startup.Gate to source connection.
1DC motor6-12 V small brushed motorControlled load.Measure stall current safely if possible.
1Fuse and supply capacitorFuse plus 470-1000 uF electrolyticLimits faults and supports current pulses.Cap polarity correct at motor supply.

Build boundary

This guide is for small low-voltage brushed DC motors. It does not cover mains motors, e-bike controllers, car starter motors, or high-current battery systems.

Part modules vary. Read the markings and datasheet for the exact board in front of you before applying power.