# How to make a mobile phone charger (Part-1) Schematic Circuit Diagram

#### Introduction to Power Electronics Tutorial Series

This marks the inaugural tutorial in the power electronics series. In this comprehensive guide, we will delve into the creation of a mobile phone charger employing readily accessible components. The series is an ongoing exploration of diverse power electronics topics. In this initial installment, our focus will be on crafting a stable DC voltage source derived from the common 230 volts, 60 Hz power supply typically found in households.

#### Schematic Diagram:

To recharge a mobile phone, a 5-volt DC power source is required, with a charging current of 700 milliamps. However, the actual current needed depends on the charging duration. For rapid charging within a short period, a higher current exceeding 700 milliamps is necessary. Conversely, for extended charging periods, such as 10 hours, a lower current below 700 milliamps suffices. This requirement is also influenced by the battery’s capacity. For example, a high-capacity battery like 9000 mAh demands a higher current and longer charging duration. Therefore, the choice of battery being charged is crucial.

Additionally, the duration of charging impacts the battery life. Longer charging periods result in extended battery life, whereas rapid charging may shorten its longevity. In the provided schematic, a low current source is employed to ensure prolonged battery life.

#### Schematic Description

Above schematic can be divided into three part, in the first part, we have to convert high voltage (230 volts) AC source into low voltage (9-12) volt using a transformer. The conversion of high voltage AC source to low voltage AC source depends upon coupling factor of the transformer. Generally, we can calculate the coupling factor by dividing output voltage by input voltage but this is not accurate Generally you have to find flux of each coil and calculate blah blah blah ( do not worry you do not need to calculate coupling factor ) just use a transformer that can produce the output of 9-12 volt AC output. And if you are using Proteus to simulate the circuit then you can download the complete file from this link smooth DC generation electronify

#### Converting AC to DC

In this section of the schematic, the conversion of AC to DC becomes imperative. The voltage generated by the transformer is not in the DC form, necessitating the use of diodes for this transformation. During the first cycle of the AC source, two opposing diodes conduct electricity, and in the subsequent cycle, the other two diodes come into play. By incorporating a capacitor, the AC power supply is converted into a stable DC power source.

#### Ensuring Smooth DC Output

The converted DC source, while in the form of direct current, may not be entirely smooth; it often exhibits ripples and occasional high voltage signals. These fluctuations pose a risk to the circuit’s integrity and can lead to potential damage. To address this, a smoothing process is required. In the provided circuit, the 7805 IC is employed to regulate the DC source. However, alternative ICs like LM317 can be utilized to achieve the same objective.

#### Implementing Short Circuit Protection

While a smooth 5-volt DC source has been successfully generated, it alone does not suffice to create a charger. To enhance the circuit’s safety and durability, incorporating short circuit protection is essential. This safeguard ensures that in the event of a short circuit, the entire circuit remains unharmed. The upcoming section will delve into the implementation of short circuit protection measures.

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