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 [...]

The large issue today that caused by more electronic equipment enters the home and the office is noise of fan. to reduce fan noise, a variable speed fan is used because it permits quieter and slower, fan speed when temperature conditions allow. To build a variable speed fan we can use digital control or high-speed/low-speed [...]

If you have to provide a fan to cool your audio power amplifier final transistor, it better to turn it off when it’s not needed. This solution is good since you don’t have to hear the fan noise when you play the music with low level volume at night, the power transistor won’t get hot. [...]

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 [...]

LM56 is a monolithic  thermostat designed for simple temperature control. The chip has two programmable threshold that can be used to drive a fan and or alarm.  Here is the schematic diagram of the fan control circuit: /caption] The circuit will turn on the fan when the temperature rise above 50 [...]

This is a video tutorial of DC motor control. This video shows how to control the DC motor speed. In this video, speed of the DC motor is controlled by changing the power supply. Increasing speed can be done by increasing the voltage, and decreasing the voltage will decrease the speed of DC motor. Here [...]