4th Week

Last week, the mission to find a proper circuit is accomplished. =)# This week, we need to buy all the components in order to construct it on board. We had bought all the components at "Online Components Shop"

Firstly, we need to listed all the components needed that shown on the circuit. These are all the components list with the explanation :

1. LT 1302 (for regulated IC)

From the datasheet for this IC, the description has shown that this IC is used as a filter for a voltage. This IC is the main component to built this project because the objective of creating this project is to charge a various type of electronic devices by using USB cable. So, we do need an IC to maintain the output voltage to charge a device. If non-stable output voltage is happen in this project which means we did not using this IC as a filter, the possibility to burn the devices is high because some device need below 5v input to charge a battery. The disadvantage for this IC is just one; this IC is its cost much expensive (RM 17.50 / IC's). So, in order to protect IC from being damage during soldering process, we are using 8 pin sockets as a base to put this IC.

#Also, you can see the datasheet on this link :
> Click Here!
>>> http://www.alldatasheet.com/datasheet-pdf/pdf/70392/LINER/LT1302.html <<<

2. - 1/8W 1% 75K resistor (Violet Green Black Red Brown)
 

- 1/8W 1% 49.9K resistor (Yellow White White Red Brown)

 - 1/8W  5% 3.3K resistor (Orange Orange Red Gold )

In circuit diagram of this project, there are two voltage divider circuit to be construct; one for input voltage and another one is for output voltage. These voltage divider circuits have their own function. For the input voltage divider, this circuit is made for charging an “Apple” device. As you known that every “Apple” devices is so choosy, always different from other devices. While for output voltage divider, the circuit is built to give a feedback 5v output fixed voltage at the IC. We are using 1% resistor for voltage divider is to get a sharp value of voltage that we want. The different between 5% and 1% is more to the price because price for 5% is much cheaper than 1%.

3. 10uH power inductor, at least 1A current capability.

The power inductor is used to protect the IC from kick back that will burn the IC. The value of the inductor is depend on how we complex the circuit because this project is portable charger, so we need to use a small components to make it easy to bring everywhere.

  

4. USB type A female jack.
 

 

USB type A female jack is used to make this project charging various type of devices via USB cable.

 

5. Power supply capacitor 220uF/6.3V+ and Bypass capacitor 0.1uF

A capacitor (originally known as condenser) is a passive two-terminal electrical component used to store energy in an electric field.

6. 1N5818 (or 1N5817, etc) Schottky Diode

This diode is employing thr Schottky Barrier principle in a large area metal-to-silicon power diode. State of the art geometry features chrome barrier metal, epitaxial construction with passivation and metal overlap contact. Ideally suited for use as rectifiers in low-voltage, high frequency inverters, free wheeling diodes, and polarity protection diodes.

7. Solar Panel (Monocrystalline) 12V/5W

   

The reason why we are choosing this type of solar panel because this type of solar panel is small size and its more much practical for our project. There is another one solar panel that better than polycrystalline but the prize of that type is a bit expensive plus its hard to get in Malaysia. This solar panel will absorb a sunlight and convert into electricity that will charge a rechargeable battery.

Click Here !
>>> http://www.civicsolar.com/resource/monocrystalline-vs-polycrystalline-solar-panels  <<<

8. Rechargeable Battery (3.7V/2200mAh)

 

Lithium ion battery is one of the rechargeable batteries, the reason why this battery is chosen because this battery is small and lighter than other rechargeable battery. The capacity of the battery is depend

on the value of one battery. Usually, this amount of batter can charge 3 iPhone with full charging.

9. PCB board

This PCB board is used for place the component to make the circuit more shortly and compatible with the case that we will make..