Schematic Diagrams

Useful schematic and wiring diagrams. ✔ ✔ Enjoy electronic circuits, let your idea comes to hardware

motor control

Drill Speed Regulator

A mini-drill machine is always needed in drilling the printed circuit board. It is usually powered by batteries that limit the drill’s capacity.Using a power supply adaptor with a speed regulator like the one featured here can certainly improve the performance of the drill. The speed regulator can maintain the speed of the drill no […]

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PWM Modulator

If you ever thought of experimenting with pulse-width modulation, this circuit should get you started nicely. We’ve kept simplicity in mind and used a dual 555 timer, making the circuit a piece of cake. We have even designed a small PCB for this, so building it shouldn’t be a problem at all. This certainly isn’t […]

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ULN2003 Control Stepper Motor by Parallel Port

This is an easy to build stepper motor driver that will allow you to precisely control a unipolar stepper motor through your computer’s parallel port. With a stepper motor you can build a lot of interesting gadgets such as robots, elevator, PCB drilling mill, camera panning system, automatic fish feeder, etc. If you have never […]

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Small DC Motor Speed Controller

Electric motor has been widely used as motion control, and many  type of motor controllers  have been designed to provide variable speed drives for the motor. The best controller is the servo controller, where a precise speed control is implemented using a speed sensor in the feedback path.  The circuit of the motor controller in […]

PWM Motor Control Circuit

Speed control for dc motor (electric motor) can be implemented using open loop or closed loop. Closed loop controller, also known as servo controller,  or a feedback control, gives the best performance since the loop will maintain the actual speed to follow the reference. In simple application, an open loop controller can be enough if […]

Simple PWM Circuit Using Inverter Gates

This PWM  circuit needs only two inverter gates, so you can build up to 3 independent PWM circuit using only one IC chip, since there are at keast 6 inverter gates in one IC package. Here is the schematic diagram of the circuit: Please remember that you should connect any input pins of any unused […]


PWM Motor Control With Forward, Reverse, and Break Operation

This PWM motor control circuit provides many controls for DC motor. You can control the DC motor to rotate forward, reverse, or break until it stops. Here is the schematic diagram of the circuit: The circuit uses MOSFETS bridge to drive the motor, controlled by some logic gates and small bipolar transistors. The motor voltage […]

Simple Stepper Motor Controller

Stepper motor controller is needed to run a stepper motor, since a stepper motor cannot work by just connecting it to a power supply.  To program a stepper motor to make a complex movement, we usually need a micro controller. Fortunatelly, for a simple movement like just rotating eith a constant speed, we can use […]

Water Level Controller Circuit

Water level controller circuit described here control the water level inside a tank. There two modes available with this water level controller circuit. The first mode is empty mode, when the controller will drain the tank if the water level reach the upper limit, the pump will be used to suck the water from the […]


3 Phase AC Motor Speed Control

Controlling the speed of three phase ac motor is done by controlling the frequency of the power line supply,  since the motor is synchronized with the line frequency. Three phase ac motor speed controller is actually nothing more than three phase sine wave power inverter with variable frequency. The three phase power inverter is a […]

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