Transistor de Efeito de Campo (MOSFET): Princípios de Funcionamento (Animação)

Understanding the Functionality of Electrical Components

Introduction to Circuit Functionality

• The speaker introduces a simple example found online that illustrates the operation of electrical components, emphasizing the physical functioning of the circuit.

• It is noted that both the body and source are grounded, suggesting a connection between them.

Voltage Application and Current Observation

• The speaker describes applying voltage between the source terminal and gate, as well as between source and drain, while observing current variations in relation to gate-source voltage (Vgs).

• As Vgs increases, it is explained that this leads to an increase in channel size due to enhanced electric fields attracting more free electrons.

Resistance Changes with Voltage Increase

• Increasing RMS voltage results in higher current flow from source to drain; however, this also alters electron distribution within the channel.

• The relationship between voltage and current is not linear due to channel narrowing which increases resistance as Vds approaches a critical threshold.

Saturation Region Dynamics

• When Vds equals Vgs minus threshold voltage (Vth), there’s a point where no further current flows because the channel disconnects from the drain.

• A depletion region exists between drain and body, creating an electric field that allows electrons to continue moving into the drain despite channel disconnection.

Current Behavior in Saturation

• As Vds increases further without significant changes in channel geometry, electron flow stabilizes leading to saturation where additional increments yield minimal current change.

• The speaker notes that when Vgs exceeds Vth, there’s a parabolic variation of current with respect to increasing gate-source voltage.