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This LED flasher will blink for 10 years on a single 1.5v AA cell. My previous circuit used a blocking oscillator to generate the Vdd voltage for IC1. This circuit relies on a BOOST CONVERTER configuration (inductor-diode-capacitor) . Output voltage is high enough to drive at least 5 leds series-connected.

Step 1: 10 Year LED Flasher (V.2) at Work

Step 2: Circuit Diagram

Step 3: Astable (flash Rate)

Step 4: Monostable (pulse Width)

Step 5: Transformer

Step 6: Boost Converter

Step 7: T1 Secondary

Step 8: Start-up

Step 9: Managing Energy

Step 10: Current Drain

Step 11: For More Details and Waveforms, Watch Video

Step 12:

<p>Hi!</p><p>How to green led high bright more than??? what i should change value resistor?</p>
<p>my circuit is done but led no flash, when i connect jumper then led flash one and end? please help me</p>
<p>post an image of your circuit. See if I can help.</p>
<p>Hi, transformer 12V to (black) connect to???</p>
<p>one of the blacks to battery (+) the other to transistor Collector + diode anode +jumper. The yellow (center tap) is not used.</p>
<p>Please fix, thanks :D</p>
<p>in video, i see you use 4 capacitors, in circuit diagram: 3 capacitors??? </p>
<p>the 4th cap is for decoupling but is not mandatory. (not necessary)</p>
<p>Hi! Can i change transistor BC337 by 2N4401? I don't understand the transformer work by method and create transformer???</p><p>Sorry i noob english.</p>
<p>hi!</p><p>4401 is perfect</p>
<p>Thanks for the great starter. I used it with slight modifications to create some free form electrical sculpture.</p><p>I replaced the transistor with a mosfet TN0702N3-G Description MOSFET N-CH 20V 530MA TO92-3 because I have bad luck with transistors and I hoped to reduce the current a little more. In the circuit R2 became 10K and R3 became 0 ohms (shorted). One less component to build in. Since the mosfet is a voltage controlled device and not a current we don't need to limit the current. You might be able to see all the components in the first 2 pictures that show the free form assembly method. All the components except the transformer, battery, switch and LEDs on the secondary are soldered around the chip.</p><p>My transformer was hand made. I started with PN B64290L632X35 Description FERRITE CORE TOROID 5UH T35 and wound about 5 feet of primary and 25 feet of secondary onto it. This was done by making 3 loops 5 feet long, twisting the three loops together to form 1 strand and then wrapping the toroid. Then the ends of the loops were cut. This creates 6 wires wrapped around the toroid. 1 was used as the primary while the other 5 were soldered together to make the secondary. You can see a picture of the bare toroid. In another picture the finished transformer forms the hair / hat on the art. The flashing leds form the eyes. An unused resistor forms the mouth.</p><p>Thanks again for having the basic tested circuit online.</p>
<p>Nice work !! Thank you ! <strong>---|&gt;|---</strong></p>

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Bio: Music: my profession for over 40 years... Electronics: my beloved hobby always.
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