Okay, so today I wanted to mess around with MOSFETs and figure out their transconductance. You know, see how much the drain current changes when I wiggle the gate voltage. Sounds simple enough, right? Well, it kinda was and kinda wasn’t. Here’s how it went down.
Setting Up the Playground
First things first, I grabbed a random N-channel MOSFET from my parts bin – an IRF530, I think. Then, I needed a power supply, a couple of multimeters, and some resistors. I scrounged around and found everything I needed. It was a bit of a mess on my workbench, but hey, that’s how I roll.
The Hookup
I wired everything up on a breadboard. I connected the power supply to the drain through a resistor (I used a 1k ohm one, just to limit the current). I used the multimeter to measure and set the voltage. Then, I put another resistor (10k ohm) on the gate, also used another multimeter to measure gate voltage. And of course, I connected the source pin straight to ground. Gotta keep things simple, you know?
Taking Measurements
Now for the fun part. I started by setting the gate voltage (Vgs) to a low value, like 2 volts. Then, I measured the drain current (Id) with my multimeter. I jotted down the numbers in my notebook. Old school, I know, but it works!
- Vgs = 2V, Id = (whatever I measured)
- Vgs = 2.5V, Id = (slightly higher)
- …and so on…
I kept increasing the gate voltage in small steps, like 0.5 volts each time, and measured the drain current. I did this until I saw the drain current start to level off – that means the MOSFET was getting saturated.
Calculating the “gm”
So, transconductance (gm) is just the change in drain current divided by the change in gate voltage. Basically, how much bang for your buck you get. I picked two points from my measurements where the MOSFET was in its “active” region (that’s where the current is changing nicely with the voltage). Then, simple calculation for transconductance of the picked points.
The Wrap-up
It’s that simple, I have calculated transconductance of the MOSFET!It wasn’t rocket science, but it was a good way to get a feel for how these little transistors work. Plus, I got to play with my multimeters, which is always a win.
It was a fun little experiment. Maybe next time I’ll try it with different MOSFETs and see how the transconductance changes. Always something new to learn, right?
Okay, so today I wanted to mess around with MOSFETs and figure out their transconductance. You know, see how much the drain current changes when I wiggle the gate voltage. Sounds simple enough, right? Well, it kinda was and kinda wasn’t. Here’s how it went down.
Setting Up the Playground
First things first, I grabbed a random N-channel MOSFET from my parts bin – an IRF530, I think. Then, I needed a power supply, a couple of multimeters, and some resistors. I scrounged around and found everything I needed. It was a bit of a mess on my workbench, but hey, that’s how I roll.
The Hookup
I wired everything up on a breadboard. I connected the power supply to the drain through a resistor (I used a 1k ohm one, just to limit the current). I used the multimeter to measure and set the voltage. Then, I put another resistor (10k ohm) on the gate, also used another multimeter to measure gate voltage. And of course, I connected the source pin straight to ground. Gotta keep things simple, you know?
Taking Measurements
Now for the fun part. I started by setting the gate voltage (Vgs) to a low value, like 2 volts. Then, I measured the drain current (Id) with my multimeter. I jotted down the numbers in my notebook. Old school, I know, but it works!
- Vgs = 2V, Id = (whatever I measured)
- Vgs = 2.5V, Id = (slightly higher)
- …and so on…
I kept increasing the gate voltage in small steps, like 0.5 volts each time, and measured the drain current. I did this until I saw the drain current start to level off – that means the MOSFET was getting saturated.
Calculating the “gm”
So, transconductance (gm) is just the change in drain current divided by the change in gate voltage. Basically, how much bang for your buck you get. I picked two points from my measurements where the MOSFET was in its “active” region (that’s where the current is changing nicely with the voltage). Then, simple calculation for transconductance of the picked points.
The Wrap-up
It’s that simple, I have calculated transconductance of the MOSFET!It wasn’t rocket science, but it was a good way to get a feel for how these little transistors work. Plus, I got to play with my multimeters, which is always a win.
It was a fun little experiment. Maybe next time I’ll try it with different MOSFETs and see how the transconductance changes. Always something new to learn, right?