Light your table top with this cool White LED Lamp.
It is powered from the USB port and is ideal to take notes while browsing
internet. The USB port can provide 5 volts and 100 mA current which is sufficient
to light the LED lamp
Power to the circuit is
derived from the USB port using the
standard A type plug. To give
continuous regulated power, Zener regulation is employed. Resistor R1 restricts
base current to T1 so that output will be current regulated. Since White LED
requires minimum 3.6 volts, 4.7 volt
Zener is used to provide constant 4.7 volts to LEDs. Resistor R2 restricts LED
current to around 20 mA, so that they will not be damaged. Connect the power
lines to USB plug observing correct polarity. Use a reflector for LEDs to get
maximum illumination.
USB Reading Lamp
Reviewed by Engr Babar Ali
on
February 19, 2019
Rating:
Reviewed by Engr Babar Ali
on
February 19, 2019
Rating:
No comments: