Mobile Phone Battery Charger Circuit

Posted by Erick Widyanto

Mobile Phone Battery Charger Circuit. Mobile phone chargers available for sale are very costly. The circuit offered here may come as a low-cost option to charge mobile telephones/battery packs having a rating of 7.2 volts, for example Nokia 6110/6150.
Mobile Phone Battery Charger Circuit
Mobile Phone Battery Charger Circuit


Parts Mobile Phone Battery Charger Circuit

R1 = 1K
R2 = 47R
R3 = 10R
R4 = 47R
C1 = 1000uF-25V
D1 = LEDs any color
D2 = LEDs any color
D3 = LEDs any color
D4 = 1N4007
D5 = 1N4007
IC1 = LM7806
T1 = 9VAC Xformer 250mA
BR1 = Diode bridge 1A



Circuit Functioning:

The 220-240V AC mains supply is down-converted to 9V AC by transformer T1. The transformer output is rectified by BR1 and the positive DC supply is directly connected to the charger’s output contact, as the negative terminal is connected through present limiting resistor R2. D2 works like a power indicator with R1 becoming the present limiter and D3 indicates the charging status. Throughout the charging period, about 3 volts drop occurs across R2, which activates D3 through R3.

An external DC supply source (for instance, from a vehicle battery) may also be used to energies the charger, where R4, after polarity protection diode D5, limits the input current to a safe value. The 3-terminal positive voltage regulator LM7806 (IC1) provides a constant voltage creation of 7.8V DC since D1 connected between your common terminal (pin 2) and ground rail of IC1 enhances the output voltage to 7.8V DC. D1 also works as a power indicator for that external DC supply. After creating the circuit on a veroboard, enclose it inside a suitable cabinet. A little heat sink is suggested for IC1. Mobile Phone Battery Charger Circuit