USB Powered AA NiMH and NiCd Battery Charger





   
Specifications:
·        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)



Part Description :

R1   56kΩ ¼W, 5% resistor
R2   27kΩ ¼W, 5% resistor
R3   22kΩ ¼W, 5% resistor
R4   47kΩ ¼W, 5% resistor
R5   750Ω ¼W, 5% resistor
R6   220Ω ¼W, resistor
TR1  10kΩ @ 25°C thermistor, approx. 3.7%/C° NTC
     Radio Shack #271-110 (discontinued)
C1   0.1µF 10V capacitor
Q1   TIP32C PNP transistor, TO-220 case
Z1   LM393 dual voltage comparator IC, DIP
LED1 Red, green, or yellow LED, 10mA

Other

2-cell AA battery holder
USB cable
Small heatsink


Part    Alternative Resistor Values to use with
           Vishay #2381 640 54103 Thermistor

R1        82kΩ ¼W, 5% resistor
R2        33kΩ ¼W, 5% resistor
R3        27kΩ ¼W, 5% resistor
R4        39kΩ ¼W, 5% resistor











Sumber : http://www.stefanv.com