Electronic Components & Circuit Analysis Flashcards

What is the primary difference between a JFETand a MOSFET?

Answer: MOSFETs have an insulated gate that draws virtually no gate current

MOSFETs have a metal-oxide insulating layer between the gate and channel, resulting in extremely high gate input impedance and negligible gate current.

A transformer has 500 primary turns and 50 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?

Answer: 12 V

Turns ratio Ns/Np = Vs/Vp → Vs = 120 × (50/500) = 12 V; this is a 10:1 step-down transformer.

In a series RLC circuit at resonance, which statement is true?

Answer: Inductive and capacitive reactances are equal and cancel

At resonance, XL = XC, so they cancel and the total impedance equals only the resistance R, maximizing current.

The term 'breakdown voltage' for a capacitor refers to:

Answer: The maximum voltage before the dielectric fails

Breakdown voltage is the voltage at which the dielectric material permanently fails, allowing current to flow through the capacitor.

What is the output waveform of a half-wave rectifier fed with a 60 Hz sine wave?

Answer: Pulsating DC at 60 Hz

A half-wave rectifier passes only one half-cycle per input cycle, producing pulsating DC at the same frequency as the input (60 Hz).

In a voltage divider circuit with R1 = 10 kΩ (top) and R2 = 5 kΩ (bottom) connected to 15 V, what is the output voltage across R2?

Answer: 5 V

Vout = Vin × R2/(R1+R2) = 15 × 5k/(10k+5k) = 15 × 1/3 = 5 V.

What does a negative temperature coefficient (NTC) thermistor do as temperature increases?

Answer: Resistance decreases

NTC thermistors decrease in resistance as temperature rises, making them useful for temperature sensing and inrush current limiting.