Introduction

Choosing the right transistor for your circuit can be a tricky business, especially if you're new to the game. Two popular types of transistors are Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and Bipolar Junction Transistors (BJTs). This post will provide an unbiased comparison between MOSFETs and BJTs, with data where possible, to help you make an informed decision.

MOSFET

MOSFETs are a type of transistor that can switch between a high resistance and a low resistance. This makes them ideal for digital circuits, such as those in a computer or microcontroller. MOSFETs are also good at handling high voltages and high currents, which makes them popular in power electronic applications.

Pros:

• High input impedance
• High switching speed
• Low power consumption
• High input resistance
• High noise margin

Cons:

• More expensive than BJTs
• Susceptible to static electricity and other types of damage
• Requires a high gate voltage to turn on
• Can experience thermal runaway

BJT

BJTs are another type of transistor that make use of two PN junctions to amplify a signal. They come in two flavors, NPN and PNP, where the direction of the current flow determines the type. They are commonly used in analog circuits, and are good at amplifying signals.

Pros:

• Low cost
• Easy to control gain
• Wide operating temperature range
• High output current

Cons:

• Low input impedance
• Slower switching speed
• Heavier power consumption
• Low noise margin

Which One Should You Use?

Ultimately, the decision between MOSFETs and BJTs comes down to the specific needs of your circuit. If you require high speeds and low power consumption, MOSFETs are the way to go. If cost is a major factor and/or you're dealing with analog signals, BJTs may be the better option.

Conclusion

In conclusion, choosing the right transistor for your circuit is no small feat. MOSFETs and BJTs both have their advantages and disadvantages, and the choice comes down to the needs of your specific application. We hope this post has helped you understand the differences between the two.

References:

• Sedra, Adel S., and Kenneth C. Smith. Microelectronic Circuits. Oxford University Press, 2015.
• Razavi, Behzad. Fundamentals of Microelectronics. Wiley, 2013.
• Baliga, Bharat . Fundamentals of Power Semiconductor Devices. SEC Professional Publishing, 1995.