>
1.5v One Battery LED Light Flasher Circuit Diagram
This will flash a LED, using a single 1.5V or 1.2V cell.
| PARTS LIST | |
| R1 | 100kΩ |
| R2 | 1kΩ |
| R3 | 47Ω |
| R4 | 10kΩ |
| C1 | 0.01µF (103) |
| C2 | 10µF |
| C3 | 100µF |
| Q1 | BC547 |
| Q2 | BC557 |
| D1 | LED |
| BT1 | 1.2V or 1.5V Battery |
It will even flash a white LED even though this type of LED needs about 3.2V to 3.6V for operation.
Note the R4 in series with LED charges the C3. It does not illuminate the LED. When the two transistors conduct, the collector of the Q2 rises to rail voltage and pulls the C3 high. The negative of the C3 effectively sits on top of the positive rail. All the energy (BT1 + C3) is pumped into the LED to flash.
The circuit takes about 2mA but produces a very bright flash.
You can adjust flash rate changing R1.
 |
 |
Please send your ideas, which are very important for our success…
Flasher as in a blinky thing?
I mean, the LED flashes on and off or?
found your site on del.icio.us today and really liked it.. i bookmarked it and will be back to check it out some more later
Good. Am interesting electronic pls send me more
Great article, very detailed and good drawing of circuit. Any idea what the total current flow is in between LED flashes?
Built this yesterday on a piece of breadboard, no problems at all. I didn’t have a 0.01uF cap for C1 so I used a 0.1uF instead and it all works.
I call it my flat battery detector. When the LED stops flashing, the battery is flat. I reckon it’ll take some time for that to happen though!
What is the use of the transistor on this circuit?