Analog Electronics (Electronics)

Diodes:

• p-n junction; conducts when forward biased.
• Zener diode: voltage regulator (reverse breakdown).
• LED: light emission when forward biased.
• Photodiode: generates current with light.

Bipolar Junction Transistor (BJT):

• NPN, PNP types.
• Three terminals: Emitter (E), Base (B), Collector (C).
• Three configurations: CE, CB, CC.
• Current gain: β = I_C/I_B (typically 50-300).
• Operating regions: active, saturation, cutoff.

Field Effect Transistor (FET):

• JFET, MOSFET (depletion / enhancement).
• High input impedance.
• Voltage-controlled.

Amplifiers:

• Common Emitter (CE) amplifier: moderate gain, voltage and current amplification.
• Class A: linear, low efficiency.
• Class B: push-pull.
• Class AB: practical hybrid.
• Class C: RF.

Operational Amplifier (Op-amp):

• Open-loop gain: very high (∞ ideal).
• Input impedance: very high (∞ ideal).
• Output impedance: very low (0 ideal).
• Inverting amplifier: gain = −R_f/R_in.
• Non-inverting amplifier: gain = 1 + R_f/R_in.

Op-amp applications:

• Summing, integration, differentiation.
• Filters (Sallen-Key, etc.).
• Comparators (with hysteresis = Schmitt trigger).

Filters:

• Low-pass: allows low frequencies.
• High-pass: allows high frequencies.
• Band-pass: allows specific range.
• Band-stop / notch: rejects specific range.

Oscillators:

• RC: Wien bridge, phase shift.
• LC: Hartley, Colpitts.
• Crystal: very stable frequency.

Rectifier & Filter:

• Bridge rectifier + capacitor filter = DC supply.
• Voltage regulator (78xx, 79xx series).

RRB JE focus: transistor configurations, op-amp inverting/non-inverting, rectifier types.