TOP ELECTRONICS QUESTIONS FOR INTERVIEW
Q. What is difference between Electrical and Electronics?
A. Electrical: An electric supply use for domestic as well as commercial purposes is alternating in nature. Electrical device changes the current into another form of energy like heat, light, etc. Electrical devices use copper and aluminium wires for the flow of electrical current.
Electronics: Electronics essentially deals with electronics devices and their utilization. An electronic device is that in which current flows through a vacuum or gas or semiconductor. Electronic device controls the movement of electrons for performing the operation. Electronics devices use the semiconductor material.
Q. What is communication?
A. Communication: Communication is the process to send or receive information from transmitter and receiver and vice versa & sender to receiver or one entity to other entity.
Q. Different types of communication. Explain?
A. There are two types of communication:
- Analog communication
- Digital communication
Analog communication: Analog communication is a continuous signal which represents physical measurements. Analog transmission denoted by sine waves. Example: Human voice in air and analog electronic devices etc.
Digital communication: Digital signals are discrete time signals generated by digital measurement. Digital transmission denoted by square waves or pulses. Example: Computers, CDs and other digital electronic devices.
Q. What is Diode?
A. Diode: Diode is a two terminal electronic component. Diode conducts only in one direction and behaves as an open circuit in other. A diode is also known as p-n junction. Diode represents two electrodes- cathode and anode.
Q. What is transistor?
A. Transistor: A transistor consists of two p-n junctions formed by sandwiching either p-type or n-type semiconductor between a pair of opposite types. The weak signal is introduced in the low resistance, circuit and output is taken from the high resistance circuit. Therefore, a transistor transfers a signal from a low resistance to high resistance. There are two types of transistors:
- npn transistor
- pnp transistor
Q. What is sampling?
A. Sampling: Sampling is the process of obtaining a set of samples from continuous signal or wave of time.
Q. State Sampling theorem.
A. Sampling theorem: A band limited signal of finite energy, which has no frequency components higher than W hertz, is completely described by taking its samples at a rate of 2W samples per second.
If the sampling rate in any pulse modulation system exceeds twice the maximum signal frequency, the original signal can be reconstructed from the samples at the receiver with minimal distortion.
Q. What is Modulation?
A. Modulation: Modulation is the process in which some characteristics (amplitude, frequency or phase) of high frequency career wave is varied according to a low frequency modulating signal (also known as baseband signal).
Q. What is Demodulation?
A. Demodulation: Demodulation is the process of recovering the original signal from modulated wave. Demodulation is defined as reverse process of modulation.
Q. Name the modulation techniques.
A. For analog modulation:
- Amplitude modulation (AM)
- Frequency modulation (FM)
- Phase modulation (PM)
- Pulse Amplitude modulation (PAM)
- Pulse width modulation (PWM)
- Pulse position modulation (PPM)
For digital modulation:
- Pulse code modulation (PCM)
- Delta modulation (DM)
- Differential PCM
Q. Explain AM and FM.
A. AM: AM stands for Amplitude modulation. Amplitude modulation is the process in which carrier signal amplitude is varied according to instantaneous value of base band signal.
FM: FM stands for Frequency modulation. Frequency modulation is the process in which carrier signal frequency is varied according to instantaneous value of base band signal.
Q. What is base station?
A. Base station: Base station is a radio receiver/transmitter that serves as hub of the local wireless network.
Q. What is repeater?
A. In Pulse code modulation, between transmitter and receiver a device is connected to reduce the effect of noise and disturbance that device known as repeater.
Q. What is an Amplifier?
A. Amplifier: An amplifier is a device that increases the voltage, current or power of an input signal with the aid of transistor by furnishing the additional power from a separate dc source.
Q. What is a CRO?
A. CRO: CRO stands for Cathode Ray Oscilloscope. A CRO is use to study all type of waveforms and measure their peak voltage, frequency, phase difference and pulse width, rise time and fall time of pulses etc.
Q. What is an Integrated Circuit?
A. Integrated Circuits: An integrated circuit is one in which resistors, capacitors, diodes, transistors and other passive and active components are integrated in a small semiconductor chip. Integrated circuit provides higher system reliability, reduced power consumption, faster operations due to reduced reactance, better compliance and miniaturization.
Q. What is Op-Amp?
A. Op-Amp: Op-amp is stands for Operational Amplifier. An OP-AMP is a direct coupled high gain amplifier usually consisting of one or more differential amplifier.
If a signal is applied at the inverting terminal then the O/P will be out of phase. /180* phase angle.
Q. What is CDMA, FDMA and TDMA?
A. CDMA: It stands for Code Division Multiple Access. Unique code has been assign to each channel to differ from each other. Cellular system is the example of CDMA.
FDMA: It stands for Frequency division Multiple Access. Different type of frequency range is assign in FDMA. Hence, there is no interference between channels.
TDMA: It stands for Time Division Multiple Access. Certain time slots assigned to particular channel.
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