Monitoring circuit and system for esd protection device

A monitoring system, comprising:

• a monitoring server configured to output a state request signal;
• and
• at least one announciator electrically connected to the monitoring server, the announciator comprising:
• a communication module;
• a monitoring circuit configured to be electrically connected to a ESD protection device and a ground line, wherein the ESD protection device is configured to be contacted with a user's body, the ground line is configured to be connected to the ground, and the monitoring circuit comprises:
• an oscillating unit comprising a first monitoring end and a second monitoring end, wherein the first monitoring end is configured to be electrically connected to the ESD protection device and the second monitoring end is configured to be electrically connected to the ground line, and the oscillating unit is configured to output an oscillating signal in a case that the first monitoring end is not electrically connected to the ESD protection device, the ESD protection device is not contacted to the user's body, the second monitoring end is not electrically connected to the ground line, or the ground line is not connected to the ground;
• a signal processing unit electrically connected to the oscillating unit, configured to receive the oscillating signal and to output a first voltage according to the oscillating signal;
• and
• a comparator electrically connected to the signal processing unit, configured to compare the first voltage and a reference voltage and to correspondingly output an alarm signal;
• and
• a control module configured to receive the alarm signal and the state request signal, and to output a state reply signal to the monitoring server through the communication module according the alarm signal and the state request signal.