CN218565356U

CN218565356U - Emergency lamp and control circuit thereof

Info

Publication number: CN218565356U
Application number: CN202222585591.6U
Authority: CN
Inventors: 叶兵; 刘江; 杨海全
Original assignee: Zhaoqing Yingyou Lighting Technology Co ltd
Current assignee: Zhaoqing Yingyou Lighting Technology Co ltd
Priority date: 2022-09-28
Filing date: 2022-09-28
Publication date: 2023-03-03
Anticipated expiration: 2032-09-28

Abstract

The utility model discloses a control circuit, which comprises a transparent shell, wherein the transparent shell is enclosed to form a tubular lamp body; the LED lamp bar and the circuit board are respectively arranged in the lamp body, and the circuit board is electrically connected with the LED lamp bar; the plug is arranged at the end part of the lamp body to plug the lamp body, an electric connecting part penetrating through the plug is arranged on the plug, the electric connecting part positioned outside the lamp body can be plugged with an external socket to be electrically connected with commercial power, and the electric connecting part positioned inside the lamp body is electrically connected with the circuit board; the lamp body is a tubular transparent body, the LED lamp strip and the circuit board are arranged in the transparent lamp body, the lighting angle is increased, the space is saved, the appearance is more attractive, the LED lamp body and the circuit board are respectively connected with the mains supply through the electric connection part on the plug, the electric connection part can be directly plugged into an external socket, and the emergency lamp is convenient to fix and install.

Description

Emergency lamp and control circuit thereof

Technical Field

The utility model relates to an emergency light technical field, especially an emergency light and control circuit thereof.

Background

The emergency lamp is a general term of a lamp for emergency lighting, and is used for automatically starting lighting to guide people to evacuate after a normal lighting power supply is cut off; but ordinary emergency light generally adopts single or a plurality of lamp holders to throw light on, and whole lamp body is bulky, and the lamp holder is not the integral type with the lamp body the two, and the lamp holder generally sets up at the lamp body top, and circuit board and battery setting are in the lamp body, and whole shared space is great, and lamp holder illumination angle is not comprehensive enough, and is succinct pleasing to the eye inadequately to parts such as screw are generally needed in emergency light's fixed mounting, the installation of being inconvenient for.

Disclosure of Invention

An object of the utility model is to solve one of the technical problem that exists among the prior art at least, provide an emergency light and control circuit who practices thrift space, increase illumination angle and be convenient for the installation.

According to the utility model discloses emergency light of first aspect embodiment, include: the transparent shell surrounds to form a tubular lamp body; the LED lamp strip and the circuit board are respectively arranged in the lamp body, and the circuit board is electrically connected with the LED lamp strip; the plug is arranged at the end part of the lamp body to plug the lamp body, an electric connection part penetrating through the plug is arranged on the plug, the electric connection part positioned outside the lamp body can be plugged with an external socket to be electrically connected with a mains supply, and the electric connection part positioned inside the lamp body is electrically connected with the circuit board.

According to the utility model discloses emergency light has following beneficial effect at least: the lamp body is the tubulose transparent body, and LED lamp strip and circuit board all set up in transparent lamp body, have increased illumination angle, practice thrift the space, and the appearance is more pleasing to the eye to make LED lamp body and circuit board respectively with commercial power connection through the electric connection portion on the end cap, this electric connection portion can directly peg graft to outside socket on, the fixed mounting of this emergency light of being convenient for.

According to the utility model discloses emergency light, the end cap sets up the one end of lamp body, the other end of lamp body be equipped with can with outside wall connection's coupling assembling, the one end of lamp body is passed through the end cap and is directly pegged graft with the socket, and the other end passes through coupling assembling fixed mounting, makes emergency light's installation more firm.

According to the utility model discloses emergency light, coupling assembling includes connecting portion and screw, be equipped with on the connecting portion and pass the connecting hole of screw, simple structure is convenient for implement.

According to the utility model discloses control circuit of second aspect embodiment includes: the circuit board comprises a constant current power supply module, a charging detection module and an emergency control module, wherein the input end of the constant current power supply module is electrically connected with mains supply to convert alternating current into direct current, the output end of the constant current power supply module is electrically connected with the LED lamp bar and the charging detection module respectively, and the detection end of the charging detection module is electrically connected with the mains supply to detect the working state of the mains supply; the emergency control module is respectively electrically connected with the charging detection module and the LED lamp strip, and when the detection end of the charging detection module detects that the commercial power is disconnected, the emergency control module drives the LED lamp strip to illuminate.

According to the utility model discloses control circuit has following beneficial effect at least: the constant current power supply module can change alternating current into direct current constant current, and can supply power for LED lamp strip, simultaneously charge for the detection module that charges, the operating condition in order to detect the commercial power is connected with the commercial power electricity to the sense terminal of the detection module that charges, when the detection module that charges detects the commercial power disconnection, the detection module that charges supplies power for emergency control module, and emergency control module drive LED lamp strip illumination, circuit structure is simple, easy to realize, control circuit concentrates on the circuit board, the circuit board passes through the electric connection portion on the end cap and pegs graft with outside socket, this emergency light practices thrift the space, be convenient for install.

According to the embodiment of the utility model provides a control circuit, the constant current power module includes rectifier chip M1, constant current driver chip U1, resistance R1, electric capacity C2, diode D1 and transformer T1, rectifier chip M1's input is connected with the commercial power electricity, rectifier chip M1's output is parallelly connected with electric capacity C1, electric capacity C1's one end is connected with the input of constant current driver chip U1 and diode D1's positive pole electricity respectively, ground connection behind the piece selection end series connection resistance R1 of constant current driver chip U1, diode D1's negative pole respectively with electric capacity C2 with the positive pole electricity of LED lamp strip is connected, transformer T1's primary side ground connection is concatenated to the output of constant current driver chip U1, electric capacity C2 with the negative pole of LED lamp strip ground connection respectively; the capacitor C1 and the capacitor C2 play a role in filtering, the rectifier chip M1 can convert alternating current of commercial power into direct current to supply power for the constant-current drive chip U1, the voltage detected by the chip selection end of the constant-current drive chip U1 is compared with the threshold voltage set in the constant-current drive chip U1, and when the voltage of the chip selection end reaches the internal detection threshold, a power tube in the constant-current drive chip U1 is turned off, so that constant-current work is realized; and the direct current converts the voltage into a certain working voltage through a transformer T1 to supply power for a subsequent charging detection module.

According to the utility model discloses control circuit, the detection module that charges includes battery BT, detection chip U2, electric capacity C3 and diode D2, detection chip U2's zero line end is connected with the zero line electricity of commercial power, detection chip U2's live wire end is connected with the live wire electricity of commercial power, the one end of transformer T1's secondary side is connected with diode D2's positive pole electricity, diode D2's negative pole is connected with detection chip U2's feed end electricity, detection chip U2's battery end is connected with battery BT's positive pole and electric capacity C3's one end electricity respectively, the other end of electric capacity C3 and the other end of transformer T1's secondary side ground connection respectively, detection chip U2's enable end with the emergency control module electricity is connected; when the mains supply is normal, the power supply of the detection chip U2 is coupled and supplied by the transformer T1, the battery BT is in a charging state, the zero line end and the fire line end of the detection chip U2 respectively detect the state of the mains supply, and when the mains supply is disconnected, the power supply of the detection chip U2 is discharged and supplied by the battery BT, so that the structure is simple and the implementation is easy.

According to the utility model discloses control circuit, the detection module that charges still includes the steady voltage filtering unit, the steady voltage filtering unit includes resistance R3, resistance R4, electric capacity C4 and zener diode ZD1, resistance R3's one end and electric capacity C4's one end respectively with diode D2's negative electricity connection, resistance R3's other end resistance R4's one end is connected with the feed end electricity that detects chip U2 respectively, resistance R4's the other end is connected with zener diode ZD 1's negative pole electricity, zener diode ZD 1's positive pole and electric capacity C4's the other end ground connection respectively, hinder R3, resistance R4, electric capacity C4 plays the filtering action, zener diode ZD1 plays the voltage stabilizing effect.

According to the utility model discloses control circuit, the detection module that charges still includes transformer T2 and diode D3, and battery BT's positive pole is connected with transformer T2 once the one end electricity on side, and transformer T2 secondary side's one end is connected with diode D3's positive pole electricity, diode D3's negative pole with LED lamp strip's anodal electricity is connected, battery BT's negative pole and transformer T2 secondary side's other end ground connection, transformer T2 secondary side's the other end with emergency control module electricity is connected, and after the commercial power disconnection, battery BT is LED lamp strip and emergency control module power supply respectively, and LED lamp strip's operating voltage is different with emergency control module's operating voltage, consequently converts battery BT's voltage into the operating voltage who is applicable to LED lamp strip through transformer T2, and transformer T2's once is to emergency control module power supply, simple structure, easy to implement.

According to the utility model discloses control circuit, emergency control module includes PWM chip U3, resistance R5, resistance R6 and field effect transistor Q1, the anodal power end electricity with PWM chip U3 of battery BT, detect that the enable end of chip U2 is connected with PWM chip U3's input electricity, PWM chip U3's PWM signal end is connected with field effect transistor Q1's grid electricity through concatenation resistance R5, field effect transistor Q1's source electrode is through concatenation resistance R6 ground connection, field effect transistor Q1's drain electrode is connected with the other end electricity of transformer T2 secondary side; when the detection chip U2 detects that no commercial power exists, the enable end of the detection chip U2 outputs a high level to the PWM chip U3, and the PWM signal end of the PWM chip U3 outputs a PWM signal to drive the field effect tube Q1 to light the LED for emergency lighting.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The following description will further explain embodiments of the present invention with reference to the accompanying drawings;

FIG. 1 is a block diagram of an emergency light;

FIG. 2 is an exploded view of the emergency light;

FIG. 3 is a block diagram of a control circuit;

fig. 4 is a circuit configuration diagram of the control circuit.

Detailed Description

This section will describe in detail the embodiments of the present invention, preferred embodiments of the present invention are shown in the attached drawings, which are used to supplement the description of the text part of the specification with figures, so that one can intuitively and vividly understand each technical feature and the whole technical solution of the present invention, but they cannot be understood as the limitation of the protection scope of the present invention.

In the description of the present invention, it should be understood that the directional descriptions, such as the directions or positional relationships indicated by upper, lower, front, rear, left, right, etc., are based on the directions or positional relationships shown in the drawings, and are only for convenience of description and simplification of the description, but not for indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention.

In the description of the present invention, a plurality of meanings are one or more, a plurality of meanings are two or more, and the terms greater than, smaller than, exceeding, etc. are understood as excluding the number, and the terms greater than, lower than, within, etc. are understood as including the number. If there is a description of first and second for the purpose of distinguishing technical features only, this is not to be understood as indicating or implying a relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of technical features indicated.

Referring to fig. 1 to 4, the utility model discloses a control circuit, including transparent housing 10, LED lamp strip 20, circuit board 30 and end cap 40, transparent housing 10 encloses to close and forms the tubular lamp body, LED lamp strip 20 and circuit board 30 set up respectively in the lamp body, circuit board 30 is connected with LED lamp strip 20 electricity, end cap 40 sets up the tip in the lamp body with the shutoff lamp body, be equipped with the electric connection 41 that runs through end cap 40 on the end cap 40, the electric connection 41 that is located the lamp body outside can be pegged graft with outside socket and be connected with the commercial power electricity, the electric connection 41 that is located the lamp body inside is connected with circuit board 30 electricity.

The lamp body is a tubular transparent body, the LED lamp strip 20 and the circuit board 30 are both arranged in the transparent lamp body, the lighting angle is increased, the space is saved, the appearance is more attractive, the LED lamp strip 20 and the circuit board 30 are respectively connected with the mains supply through the electric connection part 41 on the plug 40, the electric connection part 41 can be directly plugged into an external socket, and the emergency lamp is convenient to fix and install.

In some embodiments, the plug 40 is disposed at one end of the lamp body, the other end of the lamp body is provided with a connecting component capable of being connected with an external wall, one end of the lamp body is directly inserted into the socket through the plug, and the other end of the lamp body is fixedly mounted through the connecting component, so that the emergency lamp is more stably mounted; the connecting assembly comprises a connecting part and a screw, and a connecting hole capable of penetrating through the screw is formed in the connecting part, so that the connecting assembly is simple in structure and convenient to implement.

In some embodiments, the plugs 40 are respectively disposed at both ends of the lamp body, and when the external socket is disposed on the left wall, the external socket can be plugged into the socket through the electrical connection portion 41 on the plug 40 at the left side of the lamp body, and when the external socket is disposed on the right wall, the external socket can be plugged into the socket through the electrical connection portion 41 on the plug 40 at the right side of the lamp body, so that the external socket is convenient to use.

The utility model discloses control circuit, include: the emergency control circuit comprises a constant current power supply module 310, a charging detection module 320 and an emergency control module 330 which are arranged on the circuit board 30, wherein the input end of the constant current power supply module 310 is electrically connected with mains supply to convert alternating current into direct current, the output end of the constant current power supply module 310 is electrically connected with the LED light bar 20 and the charging detection module 320 respectively, and the detection end of the charging detection module 320 is electrically connected with the mains supply to detect the working state of the mains supply; the emergency control module 330 is electrically connected to the charging detection module 320 and the LED light bar 20, and when the detection end of the charging detection module 320 detects that the commercial power is disconnected, the emergency control module 330 drives the LED light bar 20 to illuminate. Constant current power supply module 310 can change the alternating current into direct current constant current, and can supply power for LED lamp strip 20, simultaneously for charging detection module 320, the operating condition in order to detect the commercial power is connected with the commercial power electricity to the detection end of detection module 320 that charges, when detection module 320 detects the commercial power disconnection that charges, detection module 320 supplies power for emergency control module 330 that charges, and emergency control module 330 drives LED lamp strip 20 illumination, circuit structure is simple, and easy realization, control circuit concentrates on circuit board 30, circuit board 30 is pegged graft with outside socket through electric connection portion 41 on end cap 40, this emergency light practices thrift the space, and is convenient for install.

In some embodiments, the constant current power supply module 310 includes a rectifier chip M1, a constant current driver chip U1, a resistor R1, a capacitor C2, a diode D1, and a transformer T1, where the rectifier chip M1 is an MB10S chip, the constant current driver chip U1 is a JD9609S7 chip, an input end of the MB10S chip is electrically connected to the mains supply, an output end of the MB10S chip is connected in parallel with the capacitor C1, one end of the capacitor C1 is electrically connected to an HV end of the JD9609S7 chip and an anode of the diode D1, a CS end of the JD9609S7 chip is connected in series to the resistor R1 and then grounded, a cathode of the diode D1 is electrically connected to anodes of the capacitor C2 and the LED light bar 20 respectively, a DRAN end of the JD9609S7 chip is connected in series to the primary side of the transformer T1 and then grounded, cathodes of the capacitor C2 and the LED light bar 20 are connected to ground, and the other end of the capacitor C1 and the ROVP end of the JD 96s 7 chip are connected in series to the resistor R2 and then grounded respectively; the capacitor C1 and the capacitor C2 play a role in filtering, the MB10S chip can convert alternating current of a mains supply into direct current to supply power for the JD9609S7 chip, the voltage detected by a CS end (chip selection end) of the JD9609S7 chip is compared with the threshold voltage set in the JD9609S7 chip, and when the voltage of the chip selection end reaches an internal detection threshold, a power tube in the JD9609S7 chip is turned off, so that constant-current work is realized; and the direct current converts the voltage into a certain working voltage through a transformer T1 to supply power for a subsequent charging detection module.

In some embodiments, the charging detection module 320 includes a battery BT, a detection chip U2, a capacitor C3 and a diode D2, the detection chip U2 employs a QW2889 chip, a zero line end of the QW2889 chip is electrically connected to a zero line of a commercial power, a live line end of the QW2889 chip is electrically connected to a live line of the commercial power, one end of a secondary side of a transformer T1 is electrically connected to an anode of the diode D2, a cathode of the diode D2 is electrically connected to a VDD end of the QW2889 chip, a BT end of the QW2889 chip is electrically connected to an anode of the battery BT and one end of the capacitor C3, the other end of the capacitor C3 and the other end of the secondary side of the transformer T1 are grounded, respectively, and an enable end of the QW2889 chip is electrically connected to the emergency control module 330; when the mains supply is normal, the power supply of the QW2889 chip is coupled by a transformer T1 for power supply, the battery BT is in a charging state, the zero line end and the fire line end of the QW2889 chip respectively detect the state of the mains supply, and when the mains supply is disconnected, the power supply of the QW2889 chip is discharged by the battery BT for power supply, so that the structure is simple and the implementation is easy; moreover, the QW2889 chip has battery overcharge and over-discharge protection, and when the battery is charged to an overcharge protection set value, a 6-5 foot valve in the QW2889 chip is closed to stop charging; when the voltage of the battery is reduced to an over-discharge protection set value, a 5-3 pin valve in the QW2889 chip is closed, and discharging is stopped.

In some embodiments, the charging detection module 320 further includes a voltage stabilizing and filtering unit 321, the voltage stabilizing and filtering unit 321 includes a resistor R3, a resistor R4, a capacitor C4, and a voltage stabilizing diode ZD1, one end of the resistor R3 and one end of the capacitor C4 are respectively electrically connected to the cathode of the diode D2, one end of the resistor R4 at the other end of the resistor R3 is respectively electrically connected to the VDD terminal of the QW2889 chip, the other end of the resistor R4 is electrically connected to the cathode of the voltage stabilizing diode ZD1, the anode of the voltage stabilizing diode ZD1 and the other end of the capacitor C4 are respectively grounded, the resistor R3, the resistor R4, and the capacitor C4 perform a filtering function, and the voltage stabilizing diode ZD1 performs a voltage stabilizing function.

In some embodiments, the charging detection module 320 further includes a transformer T2 and a diode D3, a positive electrode of the battery BT is electrically connected to one end of a primary side of the transformer T2, one end of a secondary side of the transformer T2 is electrically connected to an anode of the diode D3, a cathode of the diode D3 is electrically connected to a positive electrode of the LED light bar 20, a negative electrode of the battery BT is grounded to the other end of the secondary side of the transformer T2, and the other end of the secondary side of the transformer T2 is electrically connected to the emergency control module 330.

In some embodiments, the emergency control module 330 includes a PWM chip U3, a resistor R5, a resistor R6, and a field effect transistor Q1, wherein the positive electrode of the battery BT is electrically connected to the power supply terminal of the PWM chip U3, the enable terminal of the detection chip U2 is electrically connected to the input terminal of the PWM chip U3, the PWM signal terminal of the PWM chip U3 is electrically connected to the gate of the field effect transistor Q1 via the series resistor R5, the source of the field effect transistor Q1 is grounded via the series resistor R6, and the drain of the field effect transistor Q1 is electrically connected to the other end of the secondary side of the transformer T2; when the detection chip U2 detects that no commercial power exists, the enable end of the detection chip U2 outputs a high level to the PWM chip U3, and the PWM signal end of the PWM chip U3 outputs a PWM signal to drive the field effect tube Q1 to light the LED for emergency lighting.

It is readily understood by those skilled in the art that the above-described preferred modes can be freely combined and superimposed without conflict.

The above is only the preferred embodiment of the present invention, not limiting the patent scope of the present invention, all of which are under the concept of the present invention, the equivalent structure transformation made by the contents of the specification and the drawings is utilized, or the direct or indirect application is included in other related technical fields in the patent protection scope of the present invention.

Claims

1. An emergency light, comprising:

the lamp comprises a transparent shell (10), wherein the transparent shell (10) encloses to form a tubular lamp body;

the LED lamp comprises an LED lamp bar (20) and a circuit board (30), wherein the LED lamp bar (20) and the circuit board (30) are respectively arranged in the lamp body, and the circuit board (30) is electrically connected with the LED lamp bar (20);

the lamp body comprises a plug (40), the end portion of the lamp body is arranged to be plugged, an electric connection portion penetrating through the plug (40) is arranged on the plug (40), the electric connection portion is located outside the lamp body and can be plugged with an external socket to be electrically connected with a mains supply, and the electric connection portion located inside the lamp body is electrically connected with the circuit board (30).

2. The emergency light of claim 1, wherein: the plug (40) is arranged at one end of the lamp body, and the other end of the lamp body is provided with a connecting assembly capable of being connected with an external wall.

3. An emergency light according to claim 2, wherein: the connecting component comprises a connecting portion and a screw, and a connecting hole capable of penetrating through the screw is formed in the connecting portion.

4. A control circuit, comprising: a constant current power supply module (310), a charging detection module (320) and an emergency control module (330) which are arranged on the circuit board (30) as claimed in any one of claims 1 to 3, wherein an input end of the constant current power supply module (310) is electrically connected with a mains supply to convert alternating current into direct current constant current, an output end of the constant current power supply module (310) is electrically connected with the LED light bar (20) and the charging detection module (320), respectively, and a detection end of the charging detection module (320) is electrically connected with the mains supply to detect an operating state of the mains supply; the emergency control module (330) is respectively electrically connected with the charging detection module (320) and the LED lamp bar (20), and when the detection end of the charging detection module (320) detects that the commercial power is disconnected, the emergency control module (330) drives the LED lamp bar (20) to illuminate.

5. The control circuit of claim 4, wherein: the constant current power supply module (310) comprises a rectifier chip M1, a constant current driving chip U1, a resistor R1, a capacitor C2, a diode D1 and a transformer T1, wherein the input end of the rectifier chip M1 is electrically connected with a mains supply, the output end of the rectifier chip M1 is connected with the capacitor C1 in parallel, one end of the capacitor C1 is electrically connected with the input end of the constant current driving chip U1 and the anode of the diode D1 respectively, the chip selection end of the constant current driving chip U1 is connected with the resistor R1 in series and then grounded, the cathode of the diode D1 is electrically connected with the capacitor C2 and the anode of the LED light bar (20) respectively, the output end of the constant current driving chip U1 is connected with the primary side of the transformer T1 in series and then grounded, and the cathode of the capacitor C2 and the LED light bar (20) are grounded respectively.

6. The control circuit of claim 5, wherein: the charging detection module (320) comprises a battery BT, a detection chip U2, a capacitor C3 and a diode D2, wherein a zero line end of the detection chip U2 is electrically connected with a zero line of commercial power, a live line end of the detection chip U2 is electrically connected with a live line of the commercial power, one end of a secondary side of a transformer T1 is electrically connected with an anode of the diode D2, a cathode of the diode D2 is electrically connected with a power supply end of the detection chip U2, a battery end of the detection chip U2 is electrically connected with a positive electrode of the battery BT and one end of the capacitor C3 respectively, the other end of the capacitor C3 and the other end of the secondary side of the transformer T1 are grounded respectively, and an enabling end of the detection chip U2 is electrically connected with the emergency control module (330).

7. The control circuit of claim 6, wherein: the charging detection module (320) further comprises a voltage stabilizing and filtering unit (321), the voltage stabilizing and filtering unit (321) comprises a resistor R3, a resistor R4, a capacitor C4 and a voltage stabilizing diode ZD1, one end of the resistor R3 and one end of the capacitor C4 are electrically connected with the cathode of the diode D2 respectively, one end of the resistor R4 at the other end of the resistor R3 is electrically connected with the power supply end of the detection chip U2 respectively, the other end of the resistor R4 is electrically connected with the cathode of the voltage stabilizing diode ZD1, and the anode of the voltage stabilizing diode ZD1 and the other end of the capacitor C4 are grounded respectively.

8. The control circuit of claim 6, wherein: the charging detection module (320) further comprises a transformer T2 and a diode D3, the positive electrode of the battery BT is electrically connected with one end of the primary side of the transformer T2, one end of the secondary side of the transformer T2 is electrically connected with the positive electrode of the diode D3, the negative electrode of the diode D3 is electrically connected with the positive electrode of the LED light bar (20), the negative electrode of the battery BT is grounded with the other end of the secondary side of the transformer T2, and the other end of the secondary side of the transformer T2 is electrically connected with the emergency control module (330).

9. The control circuit of claim 8, wherein: the emergency control module (330) comprises a PWM chip U3, a resistor R5, a resistor R6 and a field effect transistor Q1, wherein the positive electrode of the battery BT is electrically connected with the power supply end of the PWM chip U3, the enable end of the detection chip U2 is electrically connected with the input end of the PWM chip U3, the PWM signal end of the PWM chip U3 is electrically connected with the grid electrode of the field effect transistor Q1 through the series resistor R5, the source electrode of the field effect transistor Q1 is grounded through the series resistor R6, and the drain electrode of the field effect transistor Q1 is electrically connected with the other end of the secondary side of the transformer T2.