Lighten your desktop by using USB LED Suite Schematic

Here is a simple USB powered lamp that can be used to light your desktop during power failures.

• The circuit operates from the 5 Volt available from the USB port.
• The 5V from the USB port is passed through current limiting resistor R2 and transistor Q1.
• The base of transistor Q1 is grounded via R1 which provides a constant bias voltage for Q1 together with D2.
• The diode D1 prevents the reverse flow of current from battery.
• C1 is used as a noise filter.
• Two white LED’s are used here for the lamp, you can also use a 2 V torch bulb instead of LED’s.
• LED D3 indicates connection with USB port.

S:electronicsuite.com