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Sunday, April 2, 2023

on video you can make at Home | Automatic ON/OFF emergency light


 Automatic LED Emergency Light Circuit

This is the simple and cost effective automatic LED Emergency Light Circuit with light sensing. This system charges from main supply and gets activated when main supply is turned OFF. This emergency lamp will work for more than 8 hours (depending the battery capacity and the power consumed by the LEDs).


When power supply is turned OFF, the circuit senses the day light and according to the light it turns on the LED’s. If the light is present even though power fails the circuit turns OFF the LEDs. Here LDR (Light Dependent Resistor) is used to sense the light.


Automatic Emergency Light Circuit Principle


When power supply is available, battery charges through the battery charging circuit. When the power fails, the white LED’s which are connected MOSFET will glow based on the light condition till the battery shuts down.


When LDR (Light Dependent Resistor) is in light, the resistance of LDR is very low. As a result base of the transistor Q2 becomes high. As a result white LED’s which are connected to MOSFET turns OFF.


When the circuit is in dark, the resistance of LDR is in order of mega ohms. Now the base of the transistor becomes low, as a result transistor Q2 switches the white LED’s to ON state.  

Automatic Emergency Light Circuit Diagram

I have divided the circuit into two parts. The first one is the battery charging circuit which also acts as an indicator circuit if the mains supply is shut down. The second circuit is the emergency lights circuit using LEDs. Based on the mains supply and the lighting conditions, the emergency LEDs are turned ON or OFF.

Components for Automatic LED Emergency Light Circuit

7805 voltage regulator

Light Dependent Resistor – 2MΩ

IRF540 MOSFET

BC548 NPN Transistor

Pot – 10KΩ

High bright LEDs – 3V@15mA

Red LED – 1

10KΩ Resistors – 3

1KΩ Resistor – 1

Working of Automatic Emergency Light Circuit

Initially, when the mains power is active, the battery charging circuit will charge the battery. In case the mains power is shut down, the battery charger circuit indicates the Emergency Light circuit about mains power and activates the emergency lights circuits through the battery.


Instead of immediately turning ON the LEDs, it first reads the ambient lighting through the LDR and then if the lighting is low, the LEDs are turned ON. 

How to Operate Automatic Emergency Light Circuit?

Give the connections according to the circuit diagram.

While giving the connections, take care in such a way that there is no common connection between AC and DC supplies.

Apply the main supply to the circuit, now you can observe that LED’s will not glow and battery will charge.

Remove the AC supply and place circuit in dark, now LED’s will glow.

If you place the circuit in light, then LED’s turns OFF.

Advantages of Automatic Emergency Light Circuit

This is very simple circuit and the cost is also very less.

Power is saved because the circuit switches the LEDs based on light conditions

Automatic Emergency Light Circuit Applications

Used in child’s study rooms to avoid the sudden power failure.

As an emergency lamp in homes.

Used in security systems to switch ON the lights automatically during the power failure.

Emergency Light With Battery Charger

A very easy circuit of “variable power supply and charger” is being explained here. It is not only very much useful in the time of power cut but also used as main power supply. At your workbench, you can use this circuit to check or testing of your electronic projects. Mobile phone batteries can be charged with the help of these circuits. This circuit can work as an emergency light.

LM317 – 1

Resistor

R1 (220E) – 1

R2-R12 (220E) – 11

R13 (470E)

VR1 (100K) – 1

C1 (100uF) – 1

C2 (. 1uF) – 1

D1-D4 (1N4007) – 4

S1-S5 (on/off switch) – 5

LED1-LED12 – 12

Transformer – 1

Battery – 1

Zener diode (3.3) – 1

Components Description

LM317: It is a variable voltage supplier. It is a device with three terminals. It works on voltage range of 1.25 V to 37 V at a current of 1.5 amps.

Resistor– The flow of current in any of the circuit is being controlled by the resistor. It is basically a passive device. There are two types of resistor available i.e

Fixed Resistor – whose value of resistance is fixed

Variable Resistor – whose value of resistance can vary

Capacitor– It is used to store the electrical charges . It is also a passive device and are available in the market in two types i.e.

Polarized Capacitor – Capacitors with polarity i.e. have + and – terminal eg electrolytic capacitor

Non-Polarized Capacitor – Capacitor without any polarity e.g. ceramic and paper capacitor.

Diode – It is mainly used to allow the single directional flow of current. It is a passive device with two terminals.

Switches -Literal sense of a switch is “transform of state”. In an electrical logic, ON and OFF are the two conditions and switch assist to alter the condition of an electrical machine from ON to OFF or reverse. Firmly talking, it doesn’t turn on or off the machine; it merely creates or break the contact.

LED (Light emitting diode) – It is a semiconductor device that produces a diverse source of beam at its output. When they are electrically biased in the forward state of p-n junction it emits a narrow spectrum of light. LED are found in the market very easily in a variety of colors via red, yellow, green and many more like white, orange etc.

Transformer -A transformer  is a device which is used for transforming current from one circuit to another.  During the transformation process, characteristic of AC signal changes. For example a low voltage AC may be changed to a high voltage AC and vice versa. The working of the transformer is based on the magnetic field to build around the conductor when current flows through it. This principle is called as electromagnetic mutual induction. Transformers are made up of two coils of wire wrapped around a core.

Battery – Battery is mainly a group of one or more than one electrochemical cell and in that chemical energy that is already stored is turned into electrical energy. From the age of Volta the principles of operation have not been altered. Every cell in the battery is made up of two halves of cells which are linked in series via an electrolytic solution. While 1/3 of the cell is made up of two houses named as the anode and cathode positive ions of the anode roam from the electrolyte to the cathode.

Zener Diode – This diode work in the reverse bias  state and start conducting when the voltage achieves the break point. If you want to get stable voltage then all you need is to  couple a resistor across it so that current flow can control.

Working of Mobile Phone Battery Charger Circuit

As per your need you can take the output from  the circuit by just  flipping the different number of switches (from S3, S4 and S5) in the circuit.


 Automatic LED Emergency Light Circuit

This is the simple and cost effective automatic LED Emergency Light Circuit with light sensing. This system charges from main supply and gets activated when main supply is turned OFF. This emergency lamp will work for more than 8 hours (depending the battery capacity and the power consumed by the LEDs).


When power supply is turned OFF, the circuit senses the day light and according to the light it turns on the LED’s. If the light is present even though power fails the circuit turns OFF the LEDs. Here LDR (Light Dependent Resistor) is used to sense the light.


Automatic Emergency Light Circuit Principle


When power supply is available, battery charges through the battery charging circuit. When the power fails, the white LED’s which are connected MOSFET will glow based on the light condition till the battery shuts down.


When LDR (Light Dependent Resistor) is in light, the resistance of LDR is very low. As a result base of the transistor Q2 becomes high. As a result white LED’s which are connected to MOSFET turns OFF.


When the circuit is in dark, the resistance of LDR is in order of mega ohms. Now the base of the transistor becomes low, as a result transistor Q2 switches the white LED’s to ON state.  

Automatic Emergency Light Circuit Diagram

I have divided the circuit into two parts. The first one is the battery charging circuit which also acts as an indicator circuit if the mains supply is shut down. The second circuit is the emergency lights circuit using LEDs. Based on the mains supply and the lighting conditions, the emergency LEDs are turned ON or OFF.

Components for Automatic LED Emergency Light Circuit

7805 voltage regulator

Light Dependent Resistor – 2MΩ

IRF540 MOSFET

BC548 NPN Transistor

Pot – 10KΩ

High bright LEDs – 3V@15mA

Red LED – 1

10KΩ Resistors – 3

1KΩ Resistor – 1

Working of Automatic Emergency Light Circuit

Initially, when the mains power is active, the battery charging circuit will charge the battery. In case the mains power is shut down, the battery charger circuit indicates the Emergency Light circuit about mains power and activates the emergency lights circuits through the battery.


Instead of immediately turning ON the LEDs, it first reads the ambient lighting through the LDR and then if the lighting is low, the LEDs are turned ON. 

How to Operate Automatic Emergency Light Circuit?

Give the connections according to the circuit diagram.

While giving the connections, take care in such a way that there is no common connection between AC and DC supplies.

Apply the main supply to the circuit, now you can observe that LED’s will not glow and battery will charge.

Remove the AC supply and place circuit in dark, now LED’s will glow.

If you place the circuit in light, then LED’s turns OFF.

Advantages of Automatic Emergency Light Circuit

This is very simple circuit and the cost is also very less.

Power is saved because the circuit switches the LEDs based on light conditions

Automatic Emergency Light Circuit Applications

Used in child’s study rooms to avoid the sudden power failure.

As an emergency lamp in homes.

Used in security systems to switch ON the lights automatically during the power failure.

Emergency Light With Battery Charger

A very easy circuit of “variable power supply and charger” is being explained here. It is not only very much useful in the time of power cut but also used as main power supply. At your workbench, you can use this circuit to check or testing of your electronic projects. Mobile phone batteries can be charged with the help of these circuits. This circuit can work as an emergency light.

LM317 – 1

Resistor

R1 (220E) – 1

R2-R12 (220E) – 11

R13 (470E)

VR1 (100K) – 1

C1 (100uF) – 1

C2 (. 1uF) – 1

D1-D4 (1N4007) – 4

S1-S5 (on/off switch) – 5

LED1-LED12 – 12

Transformer – 1

Battery – 1

Zener diode (3.3) – 1

Components Description

LM317: It is a variable voltage supplier. It is a device with three terminals. It works on voltage range of 1.25 V to 37 V at a current of 1.5 amps.

Resistor– The flow of current in any of the circuit is being controlled by the resistor. It is basically a passive device. There are two types of resistor available i.e

Fixed Resistor – whose value of resistance is fixed

Variable Resistor – whose value of resistance can vary

Capacitor– It is used to store the electrical charges . It is also a passive device and are available in the market in two types i.e.

Polarized Capacitor – Capacitors with polarity i.e. have + and – terminal eg electrolytic capacitor

Non-Polarized Capacitor – Capacitor without any polarity e.g. ceramic and paper capacitor.

Diode – It is mainly used to allow the single directional flow of current. It is a passive device with two terminals.

Switches -Literal sense of a switch is “transform of state”. In an electrical logic, ON and OFF are the two conditions and switch assist to alter the condition of an electrical machine from ON to OFF or reverse. Firmly talking, it doesn’t turn on or off the machine; it merely creates or break the contact.

LED (Light emitting diode) – It is a semiconductor device that produces a diverse source of beam at its output. When they are electrically biased in the forward state of p-n junction it emits a narrow spectrum of light. LED are found in the market very easily in a variety of colors via red, yellow, green and many more like white, orange etc.

Transformer -A transformer  is a device which is used for transforming current from one circuit to another.  During the transformation process, characteristic of AC signal changes. For example a low voltage AC may be changed to a high voltage AC and vice versa. The working of the transformer is based on the magnetic field to build around the conductor when current flows through it. This principle is called as electromagnetic mutual induction. Transformers are made up of two coils of wire wrapped around a core.

Battery – Battery is mainly a group of one or more than one electrochemical cell and in that chemical energy that is already stored is turned into electrical energy. From the age of Volta the principles of operation have not been altered. Every cell in the battery is made up of two halves of cells which are linked in series via an electrolytic solution. While 1/3 of the cell is made up of two houses named as the anode and cathode positive ions of the anode roam from the electrolyte to the cathode.

Zener Diode – This diode work in the reverse bias  state and start conducting when the voltage achieves the break point. If you want to get stable voltage then all you need is to  couple a resistor across it so that current flow can control.

Working of Mobile Phone Battery Charger Circuit

As per your need you can take the output from  the circuit by just  flipping the different number of switches (from S3, S4 and S5) in the circuit.

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