Whoever drew that schematic has

questionable electronics experience.

Why do I say that ?

Nowhere in your post are the following :

1. Wire Guage

2. Wire length

3. Coil Inductance

Coils are inductors.

Inductors are rated in Henries (H), not ohms,

so a coil shown on a schematic as:

"5 ohm coil"

is basically meaningless.

Whoever created that schematic has no

electronics training because the American

Wire Guage lists the resistance in ohms

per thousand feet.

Since you have posted no wire guage let's

use 30 guage (30 AWG) as an example.

At 103 ohms per thousand feet , you

don't need a calculator to realize it is 103.2

mOhms PER FOOT. If your "target" is 5 ohms

(as inapprpriate as that is for a "coil")

then 5 ohms divided by 103.2mOhms (0.103 Ohms) = 48.5 feet.

Wouldn't it make more sense to simply instruct

someone to construct the coil with 50 feet of

30 guage wire ? (Actually , based on the photo,

that wire looks to between 40 and 30 guage (smallest to largest guage) but you can look up

the Rho (resistance constant, which is always

given for copper oneire guages ( Rho differs

for every material)

Did you measure the coil resistance ?

Did you read the mosfet datasheet for Vgs ?

Maybe 5V<Vgs in which case it won't turn on.

You could you a gate driver like the TC4427.

It runs on 12V but takes a 5V gate drive signal.