Free Circuit Diagram

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 [...]

A phase control circuit can be used to control the power delivered to an AC load. The phase control circuit control the AC waveform, cutting the cycle to give full cycle, half cycle, zero cycle, or somewhere in between. You can say this circuit is similar to a dimmer circuit, but the switching is synchronized [...]

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 [...]

Stepper motor gives a simple, low cost, and accurate position control. Stepper motor can be driven by circuit mounted close to the motor, and controlled by a remote control circuit through long cable.  The interesting thing of this circuit is that the power for both motor and the driver circuit is carried over two wires, [...]

Unlike the 10-band graphic equalizer in our previous circuit that use a gyrator circuit, this 3-band graphic equalizer circuit uses Baxandall topology, similar with the Baxandall tone control but with additional mid frequency control. The figure below shows the schematic diagram of the circuit. The operational amplifier employ an LF351 IC chip, but [...]

Sine wave oscillator can be implemented using Wien-Bridge oscillator like in our previous sine wave oscillator circuit, but now we present another method of generating sine wave signal. Using phase shifter, we can build a simple sine wave generator, as shown in the schematic diagram below: Sine wave oscillator using phase shifter has [...]