Hi,

I'm looking for a flasher using one transistor with one LED, 6 or 7 parts maximum if possible. I tried one with an optocoupler but the LED was a bit too dim, after reducing the value of the resistor in series, the circuit stopped working. I tried some diagrams with one transistor I found on youtube but there are errors on the diagrams, just an example here in this video (at 1:47 seconds) concerning the transistor and the emitter: Super Effect LED Flasher Circuit Using Only One transistor
And for some others circuits, it's not what I'm looking for.

Thanks.

 

Flashing LED

https://www.aliexpress.com/item/1005003805487781.html

 

This avalanche flashers are very unpredictable since every bjt has different breakdown.
With two transistors and few passives you can do much better oscillator with wider Vcc range, more precise freq., etc.

 

Two transistors, I know, but google Eccles Jordan and go from there; you can tweak them easily. More than 50++ years ago I even calculated the whole thing!!

Eccles Jordan, go figure!!

 

EDIT: Duh, that circuit is going to oscillate too fast...

Joule thief circuit from Wikipedia:

I wound the inductor using a small ferrite toroid core I had laying around. Worked with a supply of 0.5-1.2V. Too much voltage just turns the LED on.

I didn't keep track of the ends of wires while I was winding, so I had to find the correct polarity by trial and error.

Four components, 5 if you replace the toroid core with 2 inductors.

Have not tried this:

 

Here is the "original" 1-transistor flasher from waaaay back. For most small-signal transistors it needs at least 12 V to operate reliably.



http://www.cappels.org/dproj/simplest_LED_flasher/Simplest_LED_Flasher_Circuit.html

ak

 

You can make the joule thief flash the LED if you put a capacitor across the resistor. The value of the capacitor and supply voltage changes the frequency. For a given combination of R and C, flash rate increases with supply voltage. I put 220uF across 4.7k and it was flashing at several hertz at around 2.5V. I have 3 LEDs in series.

You're up to 5 components now.

 

Another option is to use a flasher type LED to feed base drive to a switching transistor. That is as simple as I can imagine. One extra component aside from the switch transistor.

 

Another option is to use a flasher type LED to feed base drive to a switching transistor.

But if you have a self-flashing LED, you don't need the transistor at all.

ak

 

Hi,

I'm looking for a flasher using one transistor with one LED, 6 or 7 parts maximum if possible. I tried one with an optocoupler but the LED was a bit too dim, after reducing the value of the resistor in series, the circuit stopped working. I tried some diagrams with one transistor I found on youtube but there are errors on the diagrams, just an example here in this video (at 1:47 seconds) concerning the transistor and the emitter: Super Effect LED Flasher Circuit Using Only One transistor
And for some others circuits, it's not what I'm looking for.

Thanks.

Here is another one from the same channel. Did you try this?

 

If you are eager to switch to 555 IC, here are some flashers that you can check and try.
https://www.theengineeringprojects....-project-using-555-timer-in-proteus-isis.html