Electronics

Semiconductor devices are the building blocks of modern electronics. Key semiconductor devices include:

1. Diodes:

A diode is a two-terminal electronic component that conducts current primarily in one direction. The I-V characteristic of an ideal diode is:

Where:

• I_s = reverse saturation current
• V_T = thermal voltage (≈ 26 mV at room temperature)

2. Transistors:

Bipolar Junction Transistors (BJTs) and Field-Effect Transistors (FETs) are the most common types of transistors.

For a BJT in active mode:

Where:

• I_C = collector current
• I_B = base current
• β = current gain

For a MOSFET in saturation region:

Where:

• I_D = drain current
• μ_n = electron mobility
• C_ox = gate oxide capacitance per unit area
• W/L = width-to-length ratio of the channel
• V_GS = gate-to-source voltage
• V_TH = threshold voltage

Operational amplifiers (op-amps) are high-gain voltage amplifiers with differential inputs. Common op-amp circuits include:

1. Inverting Amplifier:

2. Non-inverting Amplifier:

3. Summing Amplifier:

4. Differentiator:

5. Integrator:

Where:

• R_f = feedback resistor
• R_in = input resistor
• C = capacitor

Digital electronics deals with signals that have discrete values, typically represented as binary (0 and 1). Key concepts include:

1. Boolean Algebra:

Basic operations:

• AND: A·B or A∧B
• OR: A+B or A∨B
• NOT: Ā or ¬A

2. Logic Gates:

Truth tables for basic gates:

3. Sequential Logic:

Sequential logic circuits have memory and their outputs depend on both current and previous inputs. Examples include flip-flops and registers.

4. Combinational Logic:

Combinational logic circuits have outputs that depend only on the current inputs. Examples include multiplexers, decoders, and adders.