1) Your circuit will not work with a 555 having a power supply of only 3.3V because its datasheet says its minimum supply is 4.5V.
2) The MJE13005A needs a base current much higher than can be supplied by a 555.

 

That's not a problem Bro. When one way closes, thousands you don't know are open. I am still Contemplating why his circuit worked for him (HE went against the GODS aka Datasheet of NE555)...

 

Maybe he used a Cmos LMC555 or TLC555 instead of an antique NE555. A Cmos 555 has a minimum supply of 1.5V or 2V.
The video has no English, No schematic and no parts list.

 

I knew it! Fakers........

 

If you cannot buy common electronic parts then do gardening instead.

 

Is this what you want?
Input voltage 3.7 to 3.0 V from a 18650 battery. Input current is 4A. Battery life 30 minutes.
output voltage 12V at 1A. 12 watts.

 

I think this is beyond your ability to make this, but it is a simple one IC boost power supply. Vin 2.7 to 3.7V, out =12V @ 1A.

Here is a design with a IC and a MOSFET.

 

First, why would anybody consider selecting "Logic Level" devices for a switch-mode power supply. That is a poor choice before you get to the start. And then in post #13 we see a 40 volt power supply.
When the intention is to design a power supply the output voltage and current are the very first thing to define. Next is the source voltage, followed by the level of regulation required. And a stable, efficient, low noise, and reliable switching supply is a challenge to create for an experienced engineer.
Texas Instruments has lots of power supply design software and a large selectio of reference designs and I recommend either their website or some of the other websites of some of the other semiconductor companies. Find a reference design that provides what you need and copy it. And study the explanation of how that design works and you will learn.

 

SS - FET.........

 

SS - FET.........

THIS WAS UPLOADED IN ERROR (TWITCHY BOARD

 

 

View attachment 195329
View attachment 195330

This graph is for a device with "typical" spec's. You cannot buy this one, the one you get might have "minimum" spec's which are much worse.

 

I was looking at this part: CSD17308Q3 from TI.
It is very much on at 2.4V Gate voltage.

 

BangGood
You can not build one of these boost supplies for this price. I think it will do the job.

 

You are looking at the graph for a "typical" one. What happens if you get one with "minimum" spec's?

 

First, why would anybody consider selecting "Logic Level" devices for a switch-mode power supply. That is a poor choice before you get to the start. And then in post #13 we see a 40 volt power supply.
When the intention is to design a power supply the output voltage and current are the very first thing to define. Next is the source voltage, followed by the level of regulation required. And a stable, efficient, low noise, and reliable switching supply is a challenge to create for an experienced engineer.
Texas Instruments has lots of power supply design software and a large selectio of reference designs and I recommend either their website or some of the other websites of some of the other semiconductor companies. Find a reference design that provides what you need and copy it. And study the explanation of how that design works and you will learn.

Ok then. I'll use a BJT for now till I get a FET for this. The problem are not parts, The problem here is just to add the transistor. And oh, by the way, I'm gonna test it with a BJT and if it works out well, fine then. I just wanted to know a Logic Level Mosfet for it, and if I can use a BJT..
If current gives me 1A or less, then no problem.

 

If you intend to use that 555 timer-based circuit, note that it does not regulate the output voltage in any way.
It's another example of a garbage internet circuit, don't waste your time.

Use an actual switching regulator IC- there is a lot going on there, switchers are a but 50 X harder to design and use than linears.
Use WEBENCH power designer, you will see how these things really work.

https://www.digikey.com/en/product-highlight/t/texas-instruments/webench-design-center

 

Ok. Thanks.

 

Why bother building one when you can get them so cheap through the mail?
https://www.allelectronics.com/category/112/buck-boost-converters/1.html

 

They all have reduced prices maybe because they do not work properly and fail soon.