hi guys,
i want make simple dc converter...i want step up voltage 5 to 8 @ 10A>>>>>>>i want the load take the current directly from the battery and the voltage from the booster....i hope you understand what i want......

 

Understand? You mean guess. You haven't told us anything about the battery or the nature of the load, and explained why you don't use the obvious and simple solution of adding another battery to get more voltage.

 

sorry for that....

i want use this simple circuit .. but the load need too high current ..about 10A @ 8v....i am making small heater for my project ....the coil always damage after seconds...i wonder if i could take the output voltage(8V) from the booster but i take the current from the battery ....the battery can handle this current
and i need variable voltage so i can't adding another battery to get more voltage

 

These are education:

http://www.dos4ever.com/flyback/flyback.html

http://www.ti.com/ww/en/simple_switcher/index.html?DCMP=simple_switcher&HQS=switcher

 

You circuit doesn't really do anything except short the 9V battery about half the time. A 100 Ω load requires 90 mA. So where does this 8V @10 A come from? That's 80 watts. Your input power source will need to supply more than that, like maybe 100 Watts. There is the efficiency thing that must be satisfied.

 

the load not shown in the pic >>>

any way to decrease the amp out from boost converter>>transistor may be? how use it?

 

Another one? That's about 6 in 2 days.

 

...i am making small heater for my project ....the coil always damage after seconds...

Let's start with that. What are the details of your coil; how much voltage and/or current does it require? What were you doing when it was damaged? What are the specs of your 9V supply - is it really a small 9V battery?

 

5 pics 4V battery....the dc boost converter wrok fine and the output 5 - 8 volt....but the coil damage after seconds

i use small coil 1w>>i know it will and must damage >>>could i use transistor to take the current from the battery direct>>not throw the boost converter?

 

Wow, I can't understand any of that. You're intentionally blowing up your coil? Why then do you care about the voltage?

Please - we cannot read minds. We need details. A schematic would go a very long way.

 

Wow, I can't understand any of that. You're intentionally blowing up your coil? Why then do you care about the voltage?

Please - we cannot read minds. We need details. A schematic would go a very long way.

I think they teach textspeak at most Community Colleges. If that doesn't work hire a teenager for the summer.

 

ok thanks all...i will buy big coil that can handle high current

 

How did you get from needing a DC-DC converter to getting a bigger coil?

 

i have dc boost converter...mosfet+coil+diode+cap.......the coil 150 uh 1W ...i will buy bigger coil 150 uh ..

 

If you want a 10A output, your coil (inductor) will need to be able to handle at least 20A without saturating.

 

Oooooooh, now I get it. I thought he was talking about his heater coil burning up, not the inductor in the boost circuit.