What causes the depletion region?

A P-N junction mimics a closed switch when it ___________.

Which of the following statements is/are true in respect of the basic charge transport mechanism: (a) Drift current is due to applied electric field (b) Diffusion current is due to a charge gradient.

An electron is a negatively charged particle having negligible mass. Some of the important properties of an electron are: (a) Charge on an electron, e = 1.602 x 10^-19 C (b) Mass of an electron, m = 9.107 x 10^-36 kg (c) Radius of electron, r = 1.9 x 10^-15 cm (d) Ratio of e/m of an electron = 1.759 x 10¹¹ C/kg Which of the above properties is/are correct?

Consider the following statements over Reverse bias voltage, (N region positive w.r.t. the P region) (a) It increases the potential barrier. (b) It decreases the space charge width. (c) It decreases the magnitude of electric field. Which of the above statements are correct?

Consider the following statements regarding Silicon: (a) Silicon is the most common material used to build semiconductor devices. (b) Si is the main ingredient of Salt. (c) Atoms in a pure silicon wafer contains six electrons in outer orbit (called valence electrons).
Which of the above statements are false?

Consider the following statements regarding half-wave rectifier: (a) Diode converts ac input voltage to a pulsed dc output voltage (b) Diode introduces a 0.6V drop so o/p peak is 0.6V smaller than the i/p peak (c) The o/p frequency is different than the i/p frequency Which of the above statements is/are true?

Consider the following statements regarding Photo - diodes: (a) Photodiode is a 4 lead semiconductor device that transforms light energy to electric current (b) Photodiodes have very linear light v/s current characteristics (c) Photodiodes are less sensitive than photo-resistor Which of the above statements are true?

Consider the following statements regarding JFET: (a) Junction field effect transistors like BJTs are three lead semiconductor devices (b) JFETs are normally off when VG - VS = 0 (c) Unlike BJTs, JFETs do not require a bias current and are controlled by using only a voltage Which of the above statements is/are true?

Consider the following statements regarding Photo-resistors: (a) Special semiconductor crystal, such as cadmium sulfide or Copper sulfide is used to make photo-resistors (b) When this semiconductor is placed in light, electrons within its structure resist flow through the resistor because they are too strongly bound to the crystal’s atoms (c) Liberated holes contribute to the current flowing through the device Which of the above statements is/are wrong?

Consider the following statements regarding AC to DC power supply: (a) An AC to DC power supply is built using a transformer and a half-wave rectifier (b) Transformer is used to step down the voltage i/p (c) Rectifier converts AC to pulsed DC Which of the above statements is/are true?

Consider the following statements regarding Solar Cells. (a) Solar cells are photodiodes with very large surface areas (b) Solar cells yield more power (c) A single solar cell may provide up to 0.5V that can supply 0.1A when exposed to bright light Which of the statements is/are true?

Consider the following statements regarding Photo-transistor: (a) Phototransistor is a light sensitive transistor (b) When the light sensitive surface at the base is exposed to light, the collector-emitter pair of the BJT does not conduct (c) When the light sensitive surface at the base is kept in darkness, a small amount of current flows from the base to the emitter. The small base-emitter current controls the larger collector-emitter current Which of the above statements are false?

Consider the following statements regarding Tachometer. (a) A photo-diode is being used as a frequency counter or tachometer. (b) A rotating disk is connected to a rotating shaft. The rotating disk has two hole in it. (c) A frequency counter is used to count the number of electrical pulses generated. Which of the above statements is/are true?

Consider the following statements regarding 7-Segment LED Display. (a) Used for displaying numbers only (b) 8 individual LEDs are used to make up the display (c) When a voltage is applied across one of the LEDs, a portion of the 7 lights up Which of the above statements is/are false?