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#electronics basics

2 public questions tagged with this topic.

Rectifiers, Filters and Applications

The output of a half-wave rectifier without a filter is:

**Rectifier** converts AC to DC using diode unilateral conduction, half-wave conducts only during positive half-cycle when forward biased, output pulsating DC with frequency equal to input 50 Hz, full-wave with centre-tap uses two diodes conducting alternate half-cycles, output frequency 100 Hz for 50 Hz input, 120 Hz for 60 Hz input, output voltage closer to peak with capacitor filter. A half-wave rectifier outputs only the positive half-cycles of the AC input, producing a pulsating DC voltage without a steady value unless filtered. Substituting values gives Pulsating DC, which matches expect

Ref: NCERT > Physics Book > Electronic Devices > Rectifiers, Filters and Applications

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Semiconductors, Types and Energy Bands

Which of the following is NOT a characteristic of semiconductors?

**Energy bands in semiconductors** consist of valence band filled at 0 K and conduction band empty, gap E_g small ~1 eV (Si 1.1 eV, Ge 0.7 eV), insulators large gap >3 eV (C diamond 5.4 eV), conductors overlapping. Intrinsic semiconductor at 0 K behaves as insulator because no thermal excitation, at T>0 K electrons jump to conduction band leaving holes, conductivity increases with temperature. Semiconductors have intermediate resistivity ( 10⁻⁵ to 10⁶ Ω m ), covalent bonding (e.g., Si, Ge), and conductivity that increases with temperature. High conductivity ( 10² to 10⁸ S m⁻¹ ) is typical of m

Ref: NCERT > Physics Book > Electronic Devices > Semiconductors, Types and Energy Bands

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