Electronic Devices Cheatsheet

Cheat Codes & Shortcuts

• Semiconductor: Material with conductivity between conductor and insulator.
• Diode Equation: \( I = I_s (e^{V_D / (n V_T)} - 1) \), where \( I_s \) is saturation current.
• BJT Regions: Active, Saturation, Cut-off.
• MOSFET Types: Enhancement and Depletion modes.
• Ohm’s Law: \( V = I R \), applies to resistive elements.
• PN Junction: Formed by P-type and N-type semiconductors.
• Transistor Gain: \( \beta = I_C / I_B \) for BJT in active mode.
• Capacitor Impedance: \( Z_C = \frac{1}{j \omega C} \).
• Inductor Impedance: \( Z_L = j \omega L \).
• Op-Amp Golden Rules: No current into inputs, virtual short in negative feedback.

Quick Reference Table

Device	Key Property	Application
Diode	One-way current flow	Rectification, Clamping
BJT	Current-controlled, \( \beta = I_C / I_B \)	Amplification, Switching
MOSFET	Voltage-controlled, high input impedance	Switching, Power amplification
Op-Amp	High gain, differential input	Amplifiers, Filters, Oscillators
Capacitor	Stores charge, \( Q = C V \)	Filtering, Timing circuits
Inductor	Stores magnetic energy, \( V = L \frac{d i}{d t} \)	Filters, Transformers

Advice

Electronic Devices Quick Tips

• Diodes: Forward bias allows current; reverse bias blocks it.
• BJT Analysis: Use \( I_E = I_B + I_C \), and \( \beta \) for amplification.
• MOSFET Operation: Check gate voltage relative to threshold voltage \( V_{th} \).
• Op-Amp Circuits: Assume virtual short and zero input current for ideal analysis.
• Passive Components: Use impedance formulas for capacitors and inductors in AC circuits.

Electronic Devices Speed Quiz

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