Monday, November 15, 2010

WOW- How to control a high-current AC loads by DC circuit (Version2)

This is an improved version from the earlier design posted in this website. The transistor driver (RTL) is replaced by a logic-level transistor logic or DTL. Instead of a resistor at the base, switching diode is used. The purpose of the diode in this design is to prevent the discharge of the capacitor directly to the MCU via GPIO. Discharge will occur when an output of logic LOW voltage is present at the MCU’s GPIO.

The power supply of MCU may be 5volts and it can control a DC circuit with a different power supply. These are circuits having dual power supplies. Ensure both GND of these circuits are connected together. Warning! Don’t connect together the positive side of different power supplies.


There are many variations of the magnetic contactors like the three-phase type. The following illustrations are methods to be used how to interconnect the between the contacts of a magnetic contactor and the load. Magnetic contactors are normally used in AC applications. It may be used for DC applications but check the coil voltage specification before implementation.


-Webscatter, Nov152010

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