How to make a Simple Rechargeable Led Flashlight ( ultra bright )

Hello friends, Welcome to the another electronics tutorial. In this tutorial, we will learn how to make a Simple Rechargeable Led Flashlight. We will also know the working process of this project and also about the main components used in it. As we already know what is a flashlight and there is already a large number number of available flashlight in the market. But, the main reason for making this project is to made this portable but powerful and that's it. The cost of this project is also very low as compared to any normal flashlight. So friends, let's begin to make this project....

Step 1 - Getting all the things needed.

[ Circuit Parts ]

> 3V White ultra-bright led - 3 pieces. ( The number of leds depends on you, The more the number of leds, the more the amount of light means more bright ).

> 4v/1A Rechargeable battery - 1 piece. ( you can change the battery capacity according to your requirement. The Circuit will be same for that also ).

> Small Switch - 1 piece.

> Charging port - 1 piece.

> Red led - 1 piece. ( you can choose any color led you likes ).

> 100 ohm resistor - 1 piece.

> 1N4007 Diode - 1 piece.

> Perforated board / PCB - 1 piece.

> Some Wires.

[ Miscellaneous Parts ]

> Plastic Box - for Casing the project.

[ Tools Needed ]

> Soldering Iron.

> Soldering Wire.

> Soldering Flux.

> Hot Glue Gun.

> Wire Cutter.

Step 2 - Knowing about 1N4007 Diode.

1N4007 Diode

The 1N4007 Diode is a most common diode which falls under the category of Rectifier diodes. The Rectifier Diodes is a type of diode whose working is most alike to a one-way check valve used in plumbing purposes. It means that a rectifier diode allows the current to flow only in one direction ( high-low ). This is the reason for which it is most commonly used to convert A.C. current to D.C Current. 

Reverse Voltage Rating.

A Rectifier diode allows current to flow only in one direction ( Anode >> Cathode ). Therefore, the voltage must be higher at anode in compare to cathode to conduct electric current.

But when the low voltage is applied at anode in compare to cathode, the theory states that no current passes through it. In practice, however a small amount of current is passed from diode under these circumstances. If the voltage difference gets large enough, the current passing through the diode increases and the diode will break down.

Hence, the voltage rating at which the diode will break down due to applying the high voltage at cathode instead of anode is known as Reverse Voltage Rating. you may better understand  it from a example that - 

Think about the mountain peak as anode and base of mountain as cathode. Imagine you are at the peak with a large stone and your friend is at the base. Consider the stone as the current and the direction in which the stone descends is the direction of current. Assume the path of mountain from base to peak as a diode. Now, when you roll down the stone, the stone easily gets down to the base without any problem. This means that when the current passes from high to low or anode to cathode, it flows without any problem means that the diode is safe.

Now, think of a situation that your friend has to roll the stone up to the peak. He will try his best but he fails to do so and at last becomes fail. you can apply the same condition to diode means that when the current or stone flows from cathode to anode or base to peak the current or stone faces problem to go up to peak or anode and last it will break down after attaining certain limit. and the limit at which it will break down is referred to as " Reversed Voltage Rating". So, friends I think that you had understand the term " Reverse Voltage Rating ". 

e.g. - 1N4001 - 50V or less, 1N4007 - upto 1000V.

Forward Current.

When the Current is flowing in a normal way means from anode to cathode( high voltage to low voltage ), the diode is said to be "forward-biased". The maximum amount of current which is consistently conducted by diode in "forward-biased" State is 1 Ampere.

The maximum current that a diode can conduct at once is about 30 Amperes. whereas if this amount of current is passed at once from the diode, the diode will fail for approximately 8.3 milliseconds. 

Forward Voltage and Power Dissipation.

When the maximum allowance current is passed through the diode, the voltage which is dropped in the diode is about 1.1 volts. Under these conditions, the diode will dissipate 3 watts of power. 

Step 3 - Knowing the Circuit Diagram and working of circuit.

Circuit Diagram

The Circuit consists of only a few component which works together for the proper working of the rechargeable led light. The 4v battery acts as a power source for the leds and the switch controls the current which is supplied to leds for turning on and off the leds. The Charging socket is used to take 5v input from the charger pin. The positive of charging port is connected to anode (+) of 1N4007 Diode and the cathode of diode is connected to positive of battery. The diode acts as a barrier and prevents the current to flow from battery to charger and It also dissipate the 1.1V due to passing of maximum allowance current (1A) through the diode from the charger. This provides a proper voltage to the battery to get charged. ( 5v-1.1v = 3.9v ). The Negative (-) of charging socket is directly connected to negative of battery. The provides a desired current to battery required for charging and the battery gets charged. The positive of Red Led is connected to positive of charging port and the negative is connected to one pin of 100 ohm resistor. The another pin of 100 ohm resistor is connected to negative of charging port. This Led is used to give a visual indication whether the battery is charging or not. If the battery is charging, the Led glows because it gets power to glow from the charging socket and vice-versa. The 100 ohm Resistor is used to prevent the blow off of led from a large amount of current from the charger. It gives the desired power to the led to work properly without any problem.  

Circuit Diagram

Step 4 - Making the Rechargeable Led Light and testing it.

All you had to do now is to connect everything according to circuit diagram and enclose it within a plastic box for giving it a better look and test it.

So friends, that is all for this electronics tutorial. I hope you like this Electronics Project. Feel free to ask any questions from me in comment box.