I started with circuit a couple of weeks ago and saw this one on a youtube video. I want to make this but I do not know how to pick the right MOSFET. I want to use a 3.7v battery and my device would only draw 40mA max. I would like an SMD mosfet but dont know how to pick.this is the video I got this from

. http://www.falstad.com/circuit/circ...CH+vp2106 x+535+430+685+433+0+24+N-CH+2N7000

 

Yeah... you want us to watch a 10+ minute video and construct a schematic ourselves?

Do YOUR homework and sketch a schematic of the circuit and post it here.

 

the schematic is linked.... thanks

 

the schematic is linked.... thanks

Post it here.

 

its there underneath the video 'falstad'

 

Post it here.

http://www.falstad.com/circuit/circ...CH+vp2106 x+535+430+685+433+0+24+N-CH+2N7000

 

SOT23 package is easy to solder.

 

its there underneath the video 'falstad'

No it isn't. Post it here.

 

I started with circuit a couple of weeks ago and saw this one on a youtube video. I want to make this but I do not know how to pick the right MOSFET. I want to use a 3.7v battery and my device would only draw 40mA max. I would like an SMD mosfet but dont know how to pick.this is the video I got this from

. http://www.falstad.com/circuit/circuitjs.html?cct=$+1+0.000005+10.20027730826997+50+5+43 f+464+272+384+272+1+1.5 s+560+272+560+336+0+1+true r+560+176+560+272+0+100000 R+464+176+464+128+0+0+40+5+0+0+0.5 w+384+256+384+176+0 w+384+176+464+176+0 g+560+368+560+384+0 r+384+320+384+416+0+100000 g+384+416+384+448+0 w+560+176+464+176+0 f+464+320+512+320+0+1.5 w+384+320+384+288+0 w+512+304+512+272+0 w+512+272+464+272+0 w+512+272+560+272+0 w+512+336+512+368+0 w+512+368+560+368+0 w+560+368+560+336+0 s+464+320+464+400+0+1+true r+384+320+464+320+0+10000 g+464+400+464+432+0 O+384+320+320+320+1 x+221+274+365+277+0+24+P-CH+vp2106 x+535+430+685+433+0+24+N-CH+2N7000

You need what are called logic level FETs. These are FETs with a low gate to source turn on voltage. If you go to a site like Mouser you can find them in the database. I would search for say a p channel with a threshold between 1 and 2 volts in a smd package and a current between 100 and 1000 ma.
http://www.mouser.com/Semiconductor...viwbdZ1yw8q5sZ1yw8qn6Z1yw8om3Z1yw8oxgZ1yw8pzl
edit: BJT might work better (cheaper).