DIY Project for Series Mosfet Build

[DRiley]

The 15k is connected to gate and source. Yeah the picture isn't super clear.
Also for the 150 ohm resistor the gate is connected to master on/off switch and the goes through the push button.

For that 150 Ohm resistor does it matter if I get a 1/8 watt vs. a 1/4 watt??

 

[DRiley]

Sounds good.

For that 150 Ohm resistor does it matter if I get a 1/8 watt vs. a 1/4 watt??

 

[caramel]

At maximum the current (let's say with a defective mosfet where the gate is shorted to source) can be:

Imax = 9 Volts / 150 Ohms = 0.06A

with the power dissipated on the resistor:

9 volts * 0.06 = 0.54W.

So if you have a defective mosfet yes the resistor will fry too. But then you probably have bigger problems


However, in normal functioning, the gate behaves like a capacitor of a few nanoFarads so the current through the resistor will start at 0.06A but will decrease to nearly zero in a fraction of second.

In fact, after that moment, the current will be

9V / 15150 Ohm = 0.000594 A

and the power disipated completely negligible (as the 15k resistor is limiting the current to a very low value)

I'd say use whatever resistor you want for the 150.