cellphone charger
TRANSCRIPT
“ Heaven’s Light is Our Guide”Rajshahi University of Engineering and
Technology
Project Presentation
Course Name : Electronic Shop PracticeCourse No: EEE-300
Welcome To Our Presentation…
Developed By :• Imam Mehedi Hasan (101037)• Rakib Hossain (101039)• Md. Shakhawath Hossain (101043)
Portable Cellphone Charger
Project Supervisor:Dr. Md. Masud RanaAssistant ProfessorDepartment of EEE, RUET
*AbstractWhile travelling charging of mobile battery is
great problem because power supply source is not generally accessible.A fully charged battery becomes necessary especially when your distance from the nearest relay station increases.Here is a simple project using very common electronics components for charging mobile battery using AA cells & 555 timer IC which IC is an integrated circuit (chip) used in a variety of timer, pulse generation and oscillator application.Moreover by successfully completing such a project, we will understand the full process of what it is to design and manufacture an electronic device.
*Introduction Cellphone chargers are nothing but AC to DC
converters. They take an input of 220 volt AC and give an output voltage around 5Volt DC. Basically, the charger is a current-limited voltage source. Generally, cellphone battery packs require 3.6-6V DC and 180- 200mA current for charging. Current of 100mA is sufficient for charging the cellphone battery at a slow rate.
Phones have rechargeable batteries inside which need to be charged with a DC voltage (slightly higher than the battery voltage). Simple phone chargers provide this DC voltage. Ours is the one kind of this. It is a universal mobile charger so we can connect any mobile connector. For example. If we want to build a charger for Nokia then we have to install a Nokia pin or if we want to connect a Sony Ericsson mobile we can install Sony charger pins at the output.
*Apparatus
Apparatus ValuesR1 390 ΩR2 680 ΩR3 39 Ω/1WR4 27 KΩR5 47 KΩR6 3.3 KΩR7 100 Ω/1WVR1, VR2 20 KΩ
Apparatus ValuesC1 0.001 µFC2 0.01 µFC3 4.7 µF/25V
Capacitors
Resistors
*Apparatus Apparatus Values
IC1 NE555 timer ICT1 SL100ZD1 5.6 V/1WSW1 On/Off SwitchBattery 12 VLED1
*Circuit Diagram
*555 Timer IC (Pin diagram)
◊ Timer IC NE555 is used to charge and monitor the voltage level in the battery.
◊ Control voltage pin 5 of IC1 is provided with a reference voltage of 5.6V by zener diode ZD1.
◊ Threshold pin 6 is supplied with a voltage set by VR1 and trigger pin 2 is supplied with a voltage set by VR2.
◊ When the discharged cellphone battery is connected to the circuit, the voltage given to trigger pin 2 of IC1 is below 1/3Vcc and hence the flip-flop in the IC is switched on to take output pin 3 high.
◊ When the battery is fully charged, the output terminal voltage increases the voltage at pin 2 of IC1 above the trigger point threshold.
◊ This switches off the flip-flop and the output goes low to terminate the charging process.
◊ Threshold pin 6 of IC1 is referenced at 2/3Vcc set by VR1. Transistor T1 is used to enhance the charging current.
◊ Value of R3 is critical in providing the required current for charging. With the given value of 39-ohm the charging current is around 180 mA.
*Working Principle
*Experimental Setup
*ResultAt lab, the circuit was tested with a Nokia make
cellphone battery rated at 3.7V, 320 mAH. The charging current measured was about 200 mA. The status of LED1 is shown in the table.
LED StatusLoad across the
OutputLED1
No Battery Connected On
Charging Battery Blink
Fully Charged Battery Off
*Features and Benefits
Charger holds enough power to recharge your mobile devices.
Compatible with any model of cell/smart phones.Charge cell/smart phone for up to 12 hours of
additional talk time.Color LED indicates charging status.Automatic turn off charging when charging is
complete.Mobile can be charged anywhere where power is
not available.12V battery is rechargeable.
Thanks!
End Of Presentation