Relay drive circuit

A relay drive circuit electrically connected to an alternating current power source, comprising:

• a zero crossing test circuit that detects zero crossing points and obtains zero crossing regions of the alternating current power source and outputs a zero crossing detect signal, the zero crossing test circuit comprising an optocoupler electrically connected to the alternating current power source and an output port electrically connected to the optocoupler, wherein when the alternating current power source is in the zero crossing regions, the optocoupler is turned off, and the output port outputs a corresponding high zero crossing detect signal to the logic control circuit;
• a logic control circuit that receives the zero crossing detect signal and a corresponding switch control signal, the logic control circuit electrically connected to the zero crossing circuit;
• a drive power source that provides driving voltage for a relay, the drive power source electrically connected to the logic control circuit and the relay;
• a switch electrically connected the logic control circuit and the relay, wherein the switch control signal has the same phase as output signal from the logic control circuit in the zero crossing regions, and the switch is switched on or off accordingly under the control of the output signal to correspondingly power the relay on or off.