Electronics in a minute

Transistors in 1 minute

We can think transistors as electronically controlled resistors. Transistors have 3 pins from which 2 pins act as normal resistor wheras 3rd pincontrols the resistance between 2 pins. 

In BJT (Bipolar junction transistor) control pin is called the base where as other 2 are called emitter and collector.

Similarly in FET (Field effect transistor) control pin is called gate, the other 2 pins are source and drain.

While often referred to as amplifier, it doesnt create a higher voltage or a current on its own. Like anyother it obeys kirchoff's law. The resistance of transistor dynamically changes hence transistor.

BJT in 1 minute

In BJT, current flowing in the base controls the resistance between emitter and collector.

Picture it as a microscopic sandwich: a lightly doped base is snugly positioned between the emitter and collector. There are 2 types of BJT.

1. In NPN transistors, the base is made of lightly doped p-type material and is placed between two n-type regions, akin to two diodes connected anode to anode.

2. On the flip side, we have PNP transistors. Here, a lightly doped n-type material forms the base, nestled between two p-type regions.

In both PNP and NPN transistors, during regular operation, the emitter-base junction is forward biased, enabling current flow, while the base-collector junction is reverse biased. The reverse biasness hinders the flow of holes in NPN, whereas it prevent the moment of electron in PNP.

The careful adjustment of dopant concentrations in both NPN and PNP transistors is paramount. The collector, designed to handle substantial current, has the highest concentration, ensuring efficient operation. The emitter, though slightly less concentrated, compensates with a larger surface area, accommodating a greater current flow.

FET in 1 minute

The voltage applied between the gate and source terminals modulates the current from source and drain and it is linear.

MOSFET (Metal-Oxide-Semiconductor FET): In MOSFETs, an insulating layer (usually oxide) separates the gate from the semiconductor material. Applying a voltage to the gate terminal creates an electric field, influencing the conductivity between the source and drain. When a positive voltage is applied (for N-channel MOSFETs) or a negative voltage (for P-channel MOSFETs), it modulates the flow of electrons or holes, controlling the current.

JFET (Junction Field-Effect Transistor): JFETs have a channel made of semiconductor material, with voltage applied across the gate-source junction controlling the current flow. By adjusting the voltage at the gate, the width of the channel through which charge carriers flow is regulated, determining the current passing from source to drain.

 FETs serve as electronic gatekeepers, managing the flow of current in electronic circuits without consuming much power themselves. Their high input impedance, low noise, and efficiency make them ideal for various applications, including amplifiers, switches, and signal modulators, ensuring our devices function smoothly in our interconnected world. 

CMOS in 1 minute

CMOS (Complementary Metal-Oxide-Semiconductor) is a technology used to build integrated circuits, the brains of electronic devices like smartphones and computers. It uses two types of transistors, NMOS and PMOS, which work together to create efficient, low-power electronics. These transistors switch on and off quickly, allowing fast information processing with minimal energy use.

In CMOS circuits, NMOS transistors are typically represented with an arrow pointing outwards on the source terminal, while PMOS transistors have an arrow pointing inwards on the source terminal.

When the input is low (0), NMOS is off and PMOS is on, pulling the output high (1). When the input is high (1), NMOS is on and PMOS is off, pulling the output low (0). This complementary switching minimizes power consumption, using significant power only during transitions.

CMOS is popular for its efficiency, high noise immunity, and scalability, making it essential in microprocessors, memory chips, and digital circuits, leading to smaller, faster, and more power-efficient devices.

OPAM  in 1 minute

In BJT, current flowing in the base controls the resistance between emitter and collector.

Picture it as a microscopic sandwich: a lightly doped base is snugly positioned between the emitter and collector. There are 2 types of BJT.

1. In NPN transistors, the base is made of lightly doped p-type material and is placed between two n-type regions, akin to two diodes connected anode to anode.

2. On the flip side, we have PNP transistors. Here, a lightly doped n-type material forms the base, nestled between two p-type regions.

In both PNP and NPN transistors, during regular operation, the emitter-base junction is forward biased, enabling current flow, while the base-collector junction is reverse biased. The reverse biasness hinders the flow of holes in NPN, whereas it prevent the moment of electron in PNP.

The careful adjustment of dopant concentrations in both NPN and PNP transistors is paramount. The collector, designed to handle substantial current, has the highest concentration, ensuring efficient operation. The emitter, though slightly less concentrated, compensates with a larger surface area, accommodating a greater current flow.