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USB Battery Charger Circuit Nimh Nicd

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Charger Circuit LM393 op-amp based on the computer’s USB port with 5 volts on 2 AA NiMH, NiCd batteries can be recharged. Charging current of 470 pcb circuit drawing and detailed information have.

USB Battery Charger Circuit Nimh Nicd usb charger circuit testing pil sarj devresi

During charging, R1, R2, and R4 form a three-way voltage divider which yields about 1.26V at the non-inverting input of Z1a (pin 3, Vref). TR1 is a thermistor that is in direct contact with the cells being charged. It has a resistance of 10k at 25°C (77°F), which varies inversely with temperature by about 3.7% for every 1C° (1.8F°). R3 and TR1 form a voltage divider whose value is applied to the inverting input (pin 2, Vtmp). At a temperature of 20°C (68°F), TR1 is about 12k, which makes Vtmp about 1.76V.

The charger in this project is designed to charge two AA NiMH or NiCd cells of any capacity (as long as they are the same) at about 470mA. It will charge 700mAh NiCds in about 1.5 hours, 1500mAh NiMHs in about 3.5 hours, and 2500mAh NiMHs in about 5.5 hours. The charger incorporates an automatic charge cut-off circuit based on cell temperature, and the cells can be left in the charger indefinitely after cut-off.

USB Battery Charger Circuit Nimh Nicd usb battery charger schematic 120x120 USB Battery Charger Circuit Nimh Nicd usb pil sarj devresi baski devre pcb 120x120 USB Battery Charger Circuit Nimh Nicd usb charger placement 120x120

Size: 3.8″L x 1.2″W x 0.7″H (9.7cm x 3.0cm x 1.5cm).
Cells: Two AA, NiMH or NiCd
Charging Current: 470mA
Charge Termination Method: Battery Temperature (33°C)
Trickle Current: 10mA
Power Source: Desktop, Laptop, or Hub USB port
Operating Conditions: 15°C to 25°C (59°F to 77°F)

Current Battery Charging Time
700mAh NiCd 1.5HRS
1100mAh NiCd 2.5HRS
1600mAh NiMH 3.5HRS
2000mAh NiMH 4.5HRS
2500mAh NiMH 5.5HRS

Source: stefanv.com USB Battery Charger schematic pcb Alternative link: usb-battery-charger-circuit-nimh-nicd.rar

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