Browse over 10,000 Electronics Projects using the Page Numbering provided at the bottom of each Page.

0.3-1.5V LED Flashlight

0.3-1.5V LED Flashlight

It is a little wisp of a circuit that allows you to drive a blue or white LED from a low voltage. Normally, if you want to light up a blue or white LED you need to provide it with 3 – 3.5 V, like from a 3 V lithium coin cell. But a 1.5 V battery like a AA cell simply will not work.
But using the Joule Thief, it works like a charm. Not only does it work with a brand new battery, but it works until the battery is nearly dead– down to 0.3 V. That’s well below the point where your other toys will tell you the battery is dead, so it can steal every last joule of energy from the battery.

One other detail that you may need to know is the symbol and pinout of the 2N3904 transistor. In the symbol, the part with the arrow is the “emitter”, the “collector” is the end above it, that also connects to the LED, and the “base” is the wire leading off to the left, between the collector and emitter. (Also remember that the end of the LED with the flat side and short lead is the end that has the flat bar in the diagram.)

As a side note, this is not the most efficient circuit around; it’s beauty is that it works with such a low voltage. So, this is a great circuit to use with a dead or dying battery, and less so for use with a brand new battery.

Visit Here for more.

 

More Articles to Read

Single-Sided USB Charger
Single-Sided USB Charger
A FPGA controlled RGB LED MATRIX for Incredible Effects – the Hardware
A FPGA controlled RGB LED MATRIX for Incredible Effects – the Hardware
Using Nanotimers to Reduce IoT System Power Consumption by an Order of Magnitude
Using Nanotimers to Reduce IoT System Power Consumption by an Order of Magnitude
Replace a microwave’s beeping with the Windows XP startup sound
Replace a microwave’s beeping with the Windows XP startup sound
A DIY Laser Scanning Microscope
A DIY Laser Scanning Microscope
Reverse-engineering the surprisingly advanced ALU of the 8008 microprocessor
Reverse-engineering the surprisingly advanced ALU of the 8008 microprocessor
ESP8266 LED lighting: QuinLED v2.6 PCB
ESP8266 LED lighting: QuinLED v2.6 PCB
Switching LVDS Graphics in a Laptop Computer
Switching LVDS Graphics in a Laptop Computer
Teleknitting: TV-based string art
Teleknitting: TV-based string art
DIY Bubble Machine
DIY Bubble Machine
Start your day with Nerf target practice!
Start your day with Nerf target practice!
Teardown of a Peaktech 6225A
Teardown of a Peaktech 6225A

Top




Shares