The power -off alarm is composed of a power outage detection module, a built -in battery, and a power -off alarm host.The production line and other places running for hours.
Power -off alarm principle
Principles of power -off alarm: When electromagnetic power is powered, the armed iron is sucked down to contact D and E, and the working circuit is closed.When the electromagnetic is broken, the magnetism is lost, and the spring is pulled up and cuts off the working circuit.Conclusion: Electromagnetic relay is a switch that uses electromagnetic control working circuits.
Power off the alarm design
AC City Electric Electric Merchants D1 semi -wave rectifier, with resistance R1, R2, R3, and R4 series components, and a smaller voltage on R3 to control the working status of the transistor T1 and the MOS field effect tube T2.Once the power is turned off or the voltage is too low, the bee ostellar BZ1 issued an alarm.Because the diode D1 starts from a semi -wave rectification effect, the pulse DC signal is sent to the transistor T1. With the normal situation of the AC power supply, the voltage on the R3 can maintain T1 to turn on, and the field effect is in the deadline.Once the AC power grid voltage is lower than 50V, the voltage on the R3 drops to the threshold value required for T1 to turn on, T1 cut off, and the gate voltage of T2 rises.It is enough to turn T2, and the bee tweezers make a strong alarm.
Power -off alarm price

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