Okay, so, I’ve been messing around with electronics lately, and I gotta say, transistors are pretty wild. Today, let’s talk about MOSFETs and bipolar transistors. I decided to put these two types of transistors head-to-head to see how they stack up.

First off, I grabbed a bunch of MOSFETs and BJTs from my parts bin. I wanted to see how easy it is to actually use these things, so I started by setting up a simple circuit on my breadboard.
With the bipolar transistors, I noticed that I needed to supply a current to the base to get them to work. It wasn’t a big deal, I just added a resistor in series with the base to control the current. Once I did that, the BJT started conducting, and I could control the current flowing through the collector-emitter path by adjusting the base current. I thought it’s a little bit tricky.
Then I moved on to the MOSFETs. These things are a bit different. Instead of current, they use voltage to control the flow. I connected the gate to a voltage source, and as I increased the voltage, the MOSFET started conducting more and more current between the drain and source. It felt way simpler to me since I didn’t have to worry about calculating the base current like with the BJTs.
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Experimenting with Switching
Next, I wanted to see how fast these transistors could switch on and off. I set up another circuit with an LED and used a function generator to send pulses to the base or gate of the transistors.
The MOSFETs were blazing fast. They turned on and off in the blink of an eye. I could easily switch them at high frequencies without any issues. The BJTs, on the other hand, were a bit slower. They were able to keep up, to some extent, but as I increased the frequency, I could see that the LED didn’t turn on and off as cleanly as with the MOSFET. It seemed like they were struggling to keep up.
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Current Handling
I was also curious about how much current these transistors could handle. So, I hooked them up to a power supply and started increasing the load.
The MOSFETs really shined here. They were able to handle a ton of current without breaking a sweat. I pushed them pretty hard, and they just kept going. It felt like they could handle anything I threw at them. The BJTs, however, started to heat up pretty quickly as I increased the load. I had to be careful not to push them too far, or they might have gotten damaged. Not so tough compared to MOSFETs.
After all these tests, I realized that both MOSFETs and BJTs have their own strengths and weaknesses. If I need something that can switch super fast or handle a lot of current, I’d definitely go with a MOSFET. But, if I’m working on a low-current application where I need more control over the current flow, a BJT might be a better choice. Anyway, it was a fun experiment, and I learned a lot about how these two types of transistors work in practice. Hope this is helpful for you guys!