Optocoupler-based zero passage detecting circuit

Abstract

The invention relates to a zero passage detecting circuit and discloses an optocoupler-based zero passage detecting circuit consisting of input ends L and N, two current limiting resistors, a diode, an optocoupler, a triode and a plurality of resistor-capacitor units, wherein the L and N are input ends of the zero passage detecting circuit, the two current limiting resistors R1 and R2 are serially connected, one end is connected with the L, the other end is connected with the positive input end of the optocoupler U1, the other input end of the optocoupler U1 is connected with the N, the collector output end of the optocoupler U1 is connected with the base electrode of the triode Q1 and is connected with a power supply through a resistor R3, the other output end of the optocoupler U1 is connected with the emission electrode of the triode Q1 and is grounded, and the collector of the triode Q1 is connected with an external detecting port through a resistor R5. The circuit disclosed by the invention is simple in structure, low in cost, stable and reliable, convenient in use and is capable of effectively detecting the zero point of alternating current according to an edge switched by electrical level for the judgment and control of other circuits.

Description

technical field [0001] The invention relates to a zero-crossing detection circuit, in particular to a zero-crossing detection circuit based on an optocoupler. Background technique [0002] There are many types of zero-crossing detection circuits in existing circuits, but most of them have complex structures and functions. In some applications that only need a single function, such zero-crossing detection circuits with complex functions and structures are often still used to complete a single crossing. Zero detection function, on the one hand, the cost will increase, on the other hand, the instability and unreliability factors behind the complex circuit will also increase, and the number of detection and maintenance points after failure may also increase. Reduced the pass rate of the product. Contents of the invention [0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a zero-crossing detection c...

AI Technical Summary

Problems solved by technology

[0002] There are many types of zero-crossing detection circuits in existing circuits, but most of them have complex structures and functions. In some applications that only need a single function, such zero-crossing detection circuits with complex functions and structures are often still used to complete a single crossing. Zero detection function, on the one hand, the cost will increase, on the other hand, the instability and unreliability factors behind the complex circuit will also increase, and the number of detection and maintenance points after failure may also increase. Reduced product pass rate

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