When Q1 conducts Q2 also conducts since its base becomes negative. Charging current flows in the collector of Q1. To lessen the charging voltage to 4.7 volts, Zener diode D2 can be used. The output gives 20 mA current for slow charging. If more current is needed for fast charging, lessen the worth of R4 to 47 ohms to ensure that 80 mA current is going to be available. Output points are utilized to connect the charger using the cell phone. Use suitable pins with this and fasten with correct polarity.
Travel charger circuit |
R1 = 1K
R2 = 470R
R3 = 4.7K
R4 = 270R
R5 = 27R
C1 = 100uF-25V
D1 = Green LED
D2 = 4.7V/1W Zener
B1 = 1.5Vx4 Cells
S1 = On/Off Switch
Q1 = BC548
Q2 = SK100