Electronics & Software – Tips & Guide


What is the difference between a MOSFET amplifier and a BJT amplifier?

What is the difference between a MOSFET amplifier and a BJT amplifier?

The amplifiers. have a much greater input impedance. it’s a big advantage over the bjt.

They also consume less energy than the bjt. bjt has a high speed compared to a mosfet

mosfet power supply devices are used for the output stages and the other uses bipolar power junction transistors for the output stages

one is easier to obtain a gain of current and the other voltage gain, which affects the design of the stages as to which output stage is used.

each his fans and his possible to design high quality power amplifiers with either design. The mosfets are field emission transistors and the bjts are bipolar junction transistors. while both can act as amplifiers but their properties differ. for example, the base of the bjt absorbs very little current in the micro-amps, while in most cases the impedance of the gate is almost zero, almost infinite insofar as it is an insulator based on metal oxide. Therefore, the material provided by the mosfet is much more than what can be provided.

Since bjt is a trunk device, it takes power from the input source (even if it is very small), always causes a loading effect.

While the mosfet has an oxide between the two that only allows the field to interact with the channel and so no current (actually very very small) is drawn. so less loading effect!

ps: the load basically means the maximum number of transistors that you can connect to the second level connected to the first-level transistor (because each transistor in the second level consumes current of the first level)

another major difference is where the bjts are Temperature sensitive enough, Bjts are not more faithful amplifiers in different situations.

the manufacture also becomes easier with the mosfets because it takes less space and the active resistances can also be manufactured with the same manufacture of mosfet, which is not possible in case of bjts!

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