Extreme Circuits

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Mobile Phone Battery Charger

Small and portable unit, Can be assembled on veroboard

Mobile phone chargers available in the market are quite expensive. The circuit presented here comes as a low-cost alternative to charge mobile telephones/battery packs with a rating of 7.2 volts, such as Nokia 6110/6150.

Circuit Diagram

Mobile Phone Battery Charger Circuit Diagram

Mobile Phone Battery Charger Circuit Diagram


  • 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 Operation:

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, while the negative terminal is connected through current limiting resistor R2. D2 works as a power indicator with R1 serving as the current limiter and D3 indicates the charging status. During the charging period, about 3 volts drop occurs across R2, which turns on D3 through R3.

An external DC supply source (for instance, from a vehicle battery) can 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 output of 7.8V DC since D1 connected between the common terminal (pin 2) and ground rail of IC1 raises the output voltage to 7.8V DC. D1 also serves as a power indicator for the external DC supply. After constructing the circuit on a veroboard, enclose it in a suitable cabinet. A small heat sink is recommended for IC1.

Comments on this post:

jagvinder Singh

3 years ago:  is this circuit is relaible for charger sale in the market....i want to make a low cost charger for my personal business....plz help me.....& what is the cost of this ckt....

Tamara Sulie
By Tamara Sulie (+1) 0Score: 

3 years ago:  Thanks for the your effort and great sharing. Can you please let me know that can i use this charger as emergency cell phone charger for my Samsung S4?

Sudheer Gupta

2 years ago:  Thank you so much for sharing this circuit. I have already worked on wireless mobile battery charger using the circuit present in the post: http://www.electronicshub.org/wireless-mobile-battery-charger-circuit/. Now I will try to use this circuit.

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