modified 8 years ago

Project Circuit

01:19:37

Some help here would be appreciated. I'm very new to electronics, so any help with explanations would be great.  I'm wondering why the output voltage of the mosfet stays at a constant 11.1 V while the voltage on the gate fluctuates.  My hope was to have the output voltage oscillate from 11.1 V to 0V.

published 8 years ago

Robert_Kidd

8 years ago

The top right resister is only 800 milliOhms. Increase its value to something realistic, say 1kOhm or 10kOhm and see what happens.

mators11

8 years ago

Your mosfet does not saturate and so it does not open. Try increasing the input voltage. Eventually it will start switching. The other solution is setting correct MOSFET paramaters. Increase the width and it will work just fine.

BeeVape101

8 years ago

Thanks for your comments. Changing the pulse width did the trick. How do you find the pulse width of a particular mosfet though? Is it given on the data sheet?

mators11

8 years ago

It is not a pulse width but a channel width and length and its not something you find in a datasheet. It has to do with physical aspects of the mosfet.

BeeVape101

8 years ago

How do I determine the channel width and length? If it's too much to type out It would be great if you could direct me to a website that explains it.

mators11

8 years ago

Basically you don't. It's not a simple formula you can just use to determine it. Feel free to google it. Just set it so it works at certain voltage. Real mosfets have graphs detailing at which voltage they work so you know it's ok for you.

BeeVape101

8 years ago

That makes sense. Thanks for your help!

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.