Rear-phase-cut single-live-wire type wall light modulator

Abstract

The utility model relates to a rear-phase-cut single-live-wire type wall light modulator, which comprises an MOS (Metal Oxide Semiconductor) tube switch loop unit, a singlechip control unit and a direct-current power supply unit, the MOS tube switch loop unit comprises a wiring terminal J2 connected with an MOS tube Q1, a grid electrode of the MOS tube Q1 is connected with four resistors in series in sequence and then is connected with an MOS tube Q2, a drain electrode of the MOS tube Q2 is connected with a diode D2, the diode D2 is connected with a diode D1, a fixed end contact of a single-pole double-throw switch is connected with the MOS tube Q2, and two movable end contacts of the single-pole double-throw switch are connected with the wiring terminal J1 and the wiring terminal J3 respectively; the direct-current power supply unit comprises an alternating-current voltage waveform acquisition circuit, a direct-current voltage drop circuit, an overcurrent protection circuit and a filtering voltage stabilizing circuit; according to the single-chip microcomputer control unit, a linear sliding potentiometer is connected with the PC2 end of a single-chip microcomputer after being connected with a resistor in series, the linear sliding potentiometer and a rotary potentiometer are sequentially connected between the output end of the direct-current power supply unit and the ground in series, a triode Q6 is connected with a triode Q5 and then connected with the collector electrode of a triode Q7, and the base electrode of the triode Q7 is connected with the PA6 end of the single-chip microcomputer after being connected with a resistor in series.

Description

TECHNICAL FIELD

[0001] The utility model relates to a fixed installation in the wall terminal box in dimmer product, specifically, relate to a kind of wall dimmer of rear cut phase single fire. BACKGROUND

[0002] Dimmer is a kind of device for adjusting the brightness of lighting equipment, can meet the lighting demand under different scenes.Dimmer is widely used in home, office, commercial building and various places, provides comfortable, adjustable lighting environment.Current dimmer on market generally adopts thyristor as switching device, dimming circuit is relatively simple, but since thyristor dimming is through changing voltage waveform front to control LED brightness, therefore, light may appear jitter or flicker phenomenon under low brightness.

[0003] Therefore, a kind of structure simple, compatibility is high, can be stable dimming under low brightness dimmer. UTILITY MODEL CONTENT

[0004] To solve the above problems, the utility model aims at providing a kind of wall dimmer of rear cut phase single fire, its appearance size is designed according to terminal box space, and uses MOS tube instead of thyristor as switching device, since MOS tube dimming is through changing voltage waveform rear to control LED brightness, light jitter or flicker phenomenon does not appear under low brightness condition, the compatibility of the dimmer to lamp is greatly improved, effectively solve the problem of light jitter flicker under low brightness condition, improve the compatibility of lamp.

[0005] To achieve the above purpose, the utility model provides a kind of wall dimmer of rear cut phase single fire, including MOS tube switch loop unit, single-chip microcomputer control unit and direct current power unit, wherein:

[0006] The MOS tube switch loop unit includes:

[0007] The wiring terminal J2 connected to the power line, the wiring terminal J2 connects the drain of MOS tube Q1, the gate of MOS tube Q1 is connected to the resistance R7, the resistance R8, the resistance R9, the resistance R10 in series connection in turn and is connected with the gate of MOS tube Q2, the drain of MOS tube Q2 is connected to the anode of diode D2, the cathode of diode D2 is connected to the cathode of diode D1;

[0008] A single-pole double-throw switch, the fixed contact is connected with the drain of MOS tube Q2, the first movable contact of single-pole double-throw switch is connected with wiring terminal J1, the second movable contact of single-pole double-throw switch is connected with wiring terminal J3, so that single-pole double-throw switch selectively with wiring terminal J1 or wiring terminal J3 conduction.

[0009] The single-chip microcomputer control unit includes:

[0010] A single-chip microcomputer, wherein the VDD end is the power supply end of the single-chip microcomputer, and is connected to the output end of the direct current power supply unit; the PC1 end of the single-chip microcomputer is the alternating current signal acquisition end; the PC2 end of the single-chip microcomputer is the variable voltage signal acquisition end; and the PA6 end of the single-chip microcomputer is the voltage signal output end;

[0011] The straight sliding potentiometer changes its resistance value by sliding the light adjusting handle, the resistance R17 is connected in series with the straight sliding potentiometer and then connected to the PC2 end of the single-chip microcomputer; the rotary potentiometer changes its resistance value by rotating the rotary adjusting disc; the resistance R19, the straight sliding potentiometer and the rotary potentiometer are connected in series between the output end of the direct current power supply unit and the ground;

[0012] The triode Q6, the triode Q5 and the triode Q7, wherein the triode Q6, the anode of the diode D6 connected after the resistance R11 connected to the cathode of the diode D6 connected to the base of the triode Q6, the base of the triode Q6 connected to the base of the triode Q5 and the collector of the triode Q7 connected, the base of the triode Q7 connected after the resistance R15 connected in series to the PA6 end of the single-chip microcomputer; the connection wire between the emitter of the triode Q6 and the emitter of the triode Q5 connected to the resistance R8 and the resistance R9, so that the MOS tube switch loop unit is connected to the single-chip microcomputer control unit.

[0013] The direct current power supply unit comprises an alternating current voltage waveform acquisition circuit, a direct current voltage drop circuit, an overcurrent protection circuit and a filter voltage stabilization circuit, wherein:

[0014] The alternating current voltage waveform acquisition circuit comprises the diode D1 connected to the positive terminal J2, the resistance R13, the resistance R18 and the resistance R14 connected in series between the cathode of the diode D1 and the ground, and the connection wire between the resistance R18 and the resistance R14 connected to the PC1 end of the single-chip microcomputer, so as to acquire the alternating current voltage waveform;

[0015] The direct current voltage drop circuit comprises the triode Q3, the resistance R1, the resistance R2 and the resistance R3 connected in series between the collector and the base of the triode Q3, and the cathode of the three-terminal voltage stabilizer connected to the base of the triode Q3;

[0016] The overcurrent protection circuit comprises the resistance R5 and the resistance R6 connected in series between the emitter of the triode Q4 and the ground, and the connection wire between the resistance R5 and the resistance R6 connected to the reference electrode of the three-terminal voltage stabilizer;

[0017] The filter voltage stabilization circuit comprises the low-dropout linear voltage stabilizer, the capacitor C6 and the capacitor C7 connected in parallel between the input end and the ground end of the low-dropout linear voltage stabilizer, and the capacitor C8 connected in parallel between the output end and the ground end of the low-dropout linear voltage stabilizer; wherein the input end of the low-dropout linear voltage stabilizer is connected to the emitter of the triode Q4;

[0018] In the embodiment of the utility model, wherein, the MOS switch loop unit still includes: the connection between the resistance R7 and the gate of MOS Q1 is connected with the anode of diode D4, the cathode of diode D4 is connected with the connection between resistance R7 and resistance R8;The connection between resistance R10 and the gate of MOS Q2 is connected with the anode of diode D3, the cathode of diode D3 is connected with the connection between resistance R9 and resistance R10;The source of MOS Q1 and the source of MOS Q2 are all grounded;

[0019] In the embodiment of the utility model, wherein, the single-chip microcomputer control unit still includes: the adjusting disc of rotary potentiometer is connected to the resistance body of rotary potentiometer through a connecting rod, and the variable resistance end of straight sliding potentiometer is connected in parallel with the variable resistance end of rotary potentiometer through capacitor C3 and capacitor C4.

[0020] In the embodiment of the utility model, wherein, the single-chip microcomputer control unit still includes: the emitter of triode Q6 is connected with the emitter of triode Q5;The collector of triode Q5 and the emitter of triode Q7 are all grounded;

[0021] In the embodiment of the utility model, wherein, the AC voltage waveform acquisition circuit still includes: a capacitor C5 and a voltage stabilizing diode D5 are connected in parallel between the two ends of resistance R14.

[0022] In the embodiment of the utility model, wherein, the DC voltage drop circuit still includes: the emitter of triode Q3 is connected with the base of triode Q4;The anode of three-terminal voltage stabilizer is grounded;

[0023] In the embodiment of the utility model, wherein, the overcurrent protection circuit still includes: resistance R4 is connected between the base and the emitter of triode Q4.

[0024] In the embodiment of the utility model, wherein, the filter voltage stabilizing circuit still includes: the ground end of low dropout linear voltage stabilizer is grounded.

[0025] Compared with the existing dimmer, the rear cut phase single fire wall dimmer provided by the utility model uses MOS as switching device, can control the output power size by adjusting the conduction angle of MOS, changes the light intensity, and effectively solves the problem of light shaking and flashing in low brightness. BRIEF DESCRIPTION OF DRAWINGS

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a circuit schematic diagram of an embodiment of the present invention.

[0028] Figure 2 This is a circuit diagram of a MOS transistor switching circuit unit in one embodiment of the present invention.

[0029] Figure 3 This is a circuit diagram of a microcontroller control unit according to an embodiment of the present invention.

[0030] Figure 4 This is a circuit diagram of a DC power supply unit according to an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] Figure 1 This is a circuit diagram of an embodiment of the present invention, as shown below. Figure 1 As shown, this embodiment provides a post-phase-cut single-fire wall dimmer, which includes a MOSFET switching circuit unit, a DC power supply unit, and a microcontroller control unit. The dimmer in this embodiment is used as a single-unit dimming switch, wherein:

[0033] Figure 2 This is a circuit diagram of the MOS transistor switching circuit unit in one embodiment of the present invention, as shown below. Figure 2As shown, the MOS transistor switch loop unit comprises: a terminal J2 connected to a power supply live wire, the terminal J2 is connected to the drain (pin 2) of a MOS transistor Q1, the gate (pin 1) of the MOS transistor Q1 is connected to the gate (pin 1) of a MOS transistor Q2 in sequence after connecting the resistor R7, the resistor R8, the resistor R9 and the resistor R10, the drain (pin 2) of the MOS transistor Q2 is connected to the anode of a diode D2, and the cathode of the diode D2 is connected to the cathode of a diode D1; the source (pin 3) of the MOS transistor Q1 and the source (pin 3) of the MOS transistor Q2 are both grounded; a wire is led out between the resistor R7 and the gate (pin 1) of the MOS transistor Q1 and connected to the anode of a diode D4, and the cathode of the diode D4 is connected to the wire led out between the resistor R7 and the resistor R8; a wire is led out between the resistor R10 and the gate (pin 1) of the MOS transistor Q2 and connected to the anode of a diode D3, and the cathode of the diode D3 is connected to the wire led out between the resistor R9 and the resistor R10;

[0034] The fixed contact 2 of the single-pole double-throw switch S1 is connected to the drain (pin 2) of the MOS transistor Q2, the terminal J1 is connected to the movable contact 1 (first movable contact) of the single-pole double-throw switch S1, and the terminal J3 is connected to the movable contact 3 (second movable contact) of the single-pole double-throw switch S1, so that the single-pole double-throw switch S1 is selectively conducted with the terminal J1 or the terminal J3; when the dimmer is used as a unit dimmer switch, the lamp live wire can be selectively connected to the terminal J1 or the terminal J3, and the corresponding single-pole double-throw switch S1 is also connected to the corresponding movable contact 1 or movable contact 3 to realize the connection purpose of the dimmer and the lamp;

[0035] When the voltage flowing through the terminal J2 is a positive voltage, the MOS transistor Q1 and the MOS transistor Q2 are simultaneously controlled to be turned on, and the current flows through the built-in positive diode of the MOS transistor Q2 to the terminal J1 or the terminal J3 from the MOS transistor Q1 turned on in the positive half cycle; when the voltage flowing through the terminal J2 is a negative voltage, the current flows through the built-in reverse diode of the MOS transistor Q1 to the terminal J2 from the MOS transistor Q2 turned on in the negative half cycle;

[0036] Figure 3 The single-chip microcomputer control unit circuit diagram of the embodiment of the utility model is shown in the figure, Figure 3 As shown, the single-chip microcomputer control unit circuit comprises: a single-chip microcomputer U1, which has 8 pins, the 1-pin VDD end of the single-chip microcomputer U1 is a power supply end of the single-chip microcomputer U1, and the output of the direct-current power supply unit is connected to the pin; the 5-pin PC1 end of the single-chip microcomputer U1 is an alternating-current signal acquisition end; the 4-pin PC2 end of the single-chip microcomputer U1 is a variable voltage signal acquisition end, and the 2-pin PA6 end of the single-chip microcomputer U1 is a voltage signal output end;

[0037] Resistance R19, straight slide potentiometer VR1 and rotary potentiometer VR2 are connected in series between the output voltage of the DC power supply unit and the ground, the resistance value of the straight slide potentiometer VR1 can be changed by sliding the light handle, the straight slide potentiometer VR1 is connected to the 4th PC2 end of the single-chip microcomputer U1 after being connected with the resistance R17 in series, and the single-chip microcomputer 2nd PA6 end can output different voltage signals when the resistance value of the potentiometer changes; the adjusting disc of the rotary potentiometer VR2 is connected to the resistance body of the rotary potentiometer through a connecting rod, and the resistance value of the rotary potentiometer can be changed by rotating the adjusting disc; the variable resistance end of the straight slide potentiometer and the variable resistance end of the rotary potentiometer are connected in parallel with the capacitor C3 and the capacitor C4.

[0038] Triode Q6, triode Q5 and triode Q7, the collector (pin 2) of triode Q6 is connected with the anode of diode D6 after being connected with resistance R11, and the cathode of D6 is connected with the base (pin 1) of triode Q6 after being connected with resistance R12; the base (pin 1) of triode Q6 is connected with the base (pin 1) of triode Q5 and the collector (pin 2) of triode Q7, and the base (pin 1) of triode Q7 is connected with the 2nd PA6 end of single-chip microcomputer U1 after being connected with resistance R15 in series; a connecting wire is led out between the emitter (pin 3) of triode Q6 and the emitter (pin 3) of triode Q5 and connected to the resistance R8 and the resistance R9, so that the MOS tube switch loop unit is connected with the single-chip microcomputer control unit; the emitter (pin 3) of triode Q6 is connected with the emitter (pin 3) of triode Q5; the collector (pin 2) of triode Q5 and the emitter (pin 3) of triode Q7 are grounded.

[0039] Figure 4 For the DC power supply unit circuit diagram of an embodiment of the utility model, as Figure 4 Shown, the DC power supply unit includes: an AC voltage waveform acquisition circuit, a DC voltage drop circuit, an overcurrent protection circuit and a filter voltage stabilizing circuit, wherein:

[0040] The AC voltage waveform acquisition circuit includes: diode D1 connected with the positive terminal of wiring terminal J2, then resistance R13, resistance R18 and resistance 14 are connected in series and grounded, and a connecting wire is led out between resistance R18 and resistance R14 and connected with the 5th PC1 of single-chip microcomputer U1, used for collecting AC voltage waveform as the phase reference of single-chip microcomputer U1 signal output, and capacitor C5 and voltage stabilizing diode D5 are connected in parallel at the two ends of resistance R14;

[0041] The direct current voltage drop circuit comprises: a transistor Q3, a resistor R1, a resistor R2 and a resistor R3 connected in series between the collector (pin 2) and the base (pin 1) of the transistor Q3, the emitter (pin 3) of the transistor Q3 being connected to the base (pin 1) of a transistor Q4; a three-terminal voltage regulator T1, the cathode (pin 3) of the three-terminal voltage regulator T1 being connected to the base (pin 1) of the transistor Q3, the anode (pin 2) of the three-terminal voltage regulator T1 being grounded, 10V direct current voltage being output after the direct current voltage drop circuit, the anode of a diode D6 and R11 being connected, and power being supplied to the MOS tube switch loop unit.

[0042] The overcurrent protection circuit comprises: a transistor Q4, the emitter (pin 3) of the transistor Q4 being connected in series with a resistor R5 and a resistor R6 and then grounded; a wire being led out between the resistor R5 and the resistor R6 and connected to the reference electrode (pin 1) of a three-terminal voltage regulator T1, a resistor R4 being connected between the base (pin 1) and the emitter (pin 3) of the transistor Q4, the base (pin 1) of the transistor Q4 being connected to the emitter (pin 3) of a transistor Q3;

[0043] The filter voltage stabilizing circuit comprises: a low dropout linear voltage regulator V1, a capacitor C6 and a capacitor C7 being connected in parallel between the input end (pin 2) and the ground end (pin 1) of the low dropout linear voltage regulator V1, a capacitor C8 being connected in parallel between the output end (pin 3) and the ground end (pin 1) of the low dropout linear voltage regulator V1, and the ground end (pin 1) of the low dropout linear voltage regulator V1 being connected to the ground; wherein the input end (pin 2) of the low dropout linear voltage regulator V1 is connected to the emitter (pin 3) of the transistor Q4; 10V direct current voltage is reduced to 5V direct current voltage after passing through the low dropout linear voltage regulator V1, and the 5V direct current voltage provides reference voltage for the PC2 end of the single-chip microcomputer U1 after passing through a resistor R19, a straight slide potentiometer VR1 and a rotary potentiometer VR2.

[0044] The current input from the power supply live end flows through a diode D1 in positive connection, then flows through a resistor R3 and a resistor R2 to the base (pin 1) of a transistor Q3, the transistor Q3 is turned on, the current flows into the base (pin 1) of a transistor Q4 through the emitter (pin 3) of the transistor Q3, the transistor Q4 is turned on, and the current flows through the emitter (pin 3) of the transistor Q4 to the input end of a low dropout linear voltage regulator V1, the output end of the low dropout linear voltage regulator V1 is connected to the 1 pin VDD of a single-chip microcomputer U1.

[0045] In order to more clearly understand the dimmer of the utility model, the working principle of the dimmer will be described as follows, but is not limited to:

[0046] When the dimmer is used as a unit dimmer switch, the customer moves the dimmer handle according to the requirement, the voltage at the 4-pin PC2 end of the single-chip microcomputer U1 is changed according to the resistance change of the straight slide potentiometer VR1 and the rotary potentiometer VR2, and different voltage signals are output at the 2-pin PA6 end of the single-chip microcomputer U1. When the voltage signal is at a low level, the triode Q7 is cut off, the triode Q5 is cut off, the 10V direct current voltage is connected to the base (pin 1) of the triode Q6 through the series connection of the positive diode D6 and the resistor R12, the Q6 is turned on, the current at the emitter (pin 3) of the triode Q6 passes through the resistor R9 and the resistor R10 to control the MOS tube Q2 to be turned on, and the MOS tube Q1 is controlled to be turned on through the resistor R8 and the resistor R7; the width of the low level is different, the time of the triode Q7 being cut off is different, that is, the turn-on time of the MOS tube Q1 and the MOS tube Q2 is different; the longer the turn-on time of the MOS tube Q1 and the MOS tube Q2 in a voltage period is, the greater the current is, that is, the brightness of the load lamp is higher, and the brightness of the lamp can be changed by changing the width of the low level output at the 2-pin PA6 end of the single-chip microcomputer U1, so that the dimming purpose is achieved.

[0047] In another embodiment of the utility model, the dimmer can also be used as a three-position dimmer switch, when the dimmer is used as a three-position dimmer switch, another common three-position switch is needed to be used in cooperation, the wiring terminal J1 and the wiring terminal J3 are connected to two separate wiring terminals of the three-position common switch respectively; at this time, the working principle of the dimmer is the same as when the dimmer is used as a unit dimmer switch.

[0048] Those skilled in the art can understand that the drawings are only schematic diagrams of an embodiment, and the modules or processes in the drawings are not necessarily necessary for implementing the utility model.

[0049] Those skilled in the art can understand that the modules in the device in the embodiment can be distributed in the device in the embodiment according to the embodiment description, or can be located in one or more devices different from the embodiment. The modules in the above embodiment can be combined into one module, or can be further split into multiple sub-modules.

[0050] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. A trailing edge single phase wall dimmer, characterized by, It comprises a MOS switch circuit unit, a direct current power supply unit and a single-chip microcomputer control unit, wherein: The MOS switch circuit unit comprises: A terminal J2 connected to a live wire of a power supply, the terminal J2 being connected to a drain of a MOS transistor Q1, a gate of the MOS transistor Q1 being connected to a gate of a MOS transistor Q2 in series connection with a resistor R7, a resistor R8, a resistor R9 and a resistor R10 in turn, a drain of the MOS transistor Q2 being connected to an anode of a diode D2, a cathode of the diode D2 being connected to a cathode of a diode D1; A single-pole double-throw switch, a fixed contact of the single-pole double-throw switch being connected to the drain of the MOS transistor Q2, a first movable contact of the single-pole double-throw switch being connected to a terminal J1, a second movable contact of the single-pole double-throw switch being connected to a terminal J3, so that the single-pole double-throw switch selectively conducts with the terminal J1 or the terminal J3; The single-chip microcomputer control unit comprises: A single-chip microcomputer, a VDD terminal of the single-chip microcomputer being a power supply terminal of the single-chip microcomputer and being connected to an output terminal of the direct current power supply unit, a PC1 terminal of the single-chip microcomputer being an alternating current voltage waveform acquisition terminal, a PC2 terminal of the single-chip microcomputer being a variable voltage signal acquisition terminal, a PA6 terminal of the single-chip microcomputer being a voltage signal output terminal; A straight slide potentiometer and a rotary potentiometer, the straight slide potentiometer changing its resistance value by sliding a light adjusting handle, the straight slide potentiometer being connected to the PC2 terminal of the single-chip microcomputer in series connection with a resistor R17, the rotary potentiometer changing its resistance value by rotating an adjusting disc, the resistor R19, the straight slide potentiometer and the rotary potentiometer being connected in series between an output terminal of the direct current power supply unit and the ground; A transistor Q6, a transistor Q5 and a transistor Q7, wherein a collector of the transistor Q6 is connected to an anode of a diode D6 in series connection with a resistor R11, a cathode of the diode D6 being connected to a base of the transistor Q6 in series connection with a resistor R12, the base of the transistor Q6 being connected to a base of the transistor Q5 and a collector of the transistor Q7, a base of the transistor Q7 being connected to the PA6 terminal of the single-chip microcomputer in series connection with a resistor R15, a wire being led out between an emitter of the transistor Q6 and an emitter of the transistor Q5 and being connected to the resistor R8 and the resistor R9; The direct current power supply unit comprises an alternating current voltage waveform acquisition circuit, a direct current voltage drop circuit, an overcurrent protection circuit and a filter voltage stabilizing circuit.

2. The trailing edge phase single fire wall dimmer of claim 1, wherein, The alternating current voltage waveform acquisition circuit comprises a diode D1 connected to the terminal J2, a resistor R13, a resistor R18 and a resistor R14 being connected in series between a cathode of the diode D1 and the ground, a wire being led out between the resistor R18 and the resistor R14 and being connected to the PC1 terminal of the single-chip microcomputer; The direct current voltage drop circuit comprises a transistor Q3, a resistor R1, a resistor R2 and a resistor R3 being connected in series between a collector and a base of the transistor Q3, a three-terminal voltage stabilizer, a cathode of the three-terminal voltage stabilizer being connected to the base of the transistor Q3; The overcurrent protection circuit comprises a transistor Q4, a resistor R5 and a resistor R6 being connected in series between an emitter of the transistor Q4 and the ground, a wire being led out between the resistor R5 and the resistor R6 and being connected to a reference terminal of the three-terminal voltage stabilizer. The filter voltage stabilizing circuit comprises a low-dropout linear voltage stabilizer, a capacitor C6 and a capacitor C7 are connected in parallel between an input end and a ground end of the low-dropout linear voltage stabilizer, and a capacitor C8 is connected in parallel between an output end and the ground end of the low-dropout linear voltage stabilizer; wherein the input end of the low-dropout linear voltage stabilizer is connected to an emitter of a triode Q4.

3. The trailing edge phase single fire wall dimmer of claim 1 wherein, Anode of diode D4 is connected to a wire drawn between resistance R7 and gate of MOS tube Q1, cathode of diode D4 is connected to a wire drawn between resistance R7 and resistance R8; anode of diode D3 is connected to a wire drawn between resistance R10 and gate of MOS tube Q2, cathode of diode D3 is connected to a wire drawn between resistance R9 and resistance R10; source of MOS tube Q1 and source of MOS tube Q2 are both grounded.

4. The trailing edge phase single fire wall dimmer of claim 1, wherein, The adjusting disc of the rotary potentiometer is connected to the resistance body of the rotary potentiometer through a connecting rod, and the resistance variable end of the straight sliding potentiometer is connected in parallel with the resistance variable end of the rotary potentiometer through a capacitor C3 and a capacitor C4.

5. The trailing edge phase single fire wall dimmer of claim 1 wherein, Emitting electrode of triode Q6 is also connected to emitting electrode of triode Q5, and collecting electrode of triode Q5 and emitting electrode of triode Q7 are both grounded.

6. The trailing edge phase single fire wall dimmer of claim 2 wherein, A capacitor C5 and a voltage stabilizing diode D5 are also connected in parallel across resistance R14.

7. The trailing edge phase single fire wall dimmer of claim 2 wherein, Emitting electrode of triode Q3 is also connected to base of triode Q4, and anode of the three-terminal voltage stabilizer is grounded.

8. The trailing edge phase single fire wall dimmer of claim 2, wherein, Resistance R4 is connected between base and emitting electrode of triode Q4.

9. The trailing edge phase single fire wall dimmer of claim 2 wherein, The ground end of the low-dropout linear voltage stabilizer is grounded.

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