Electronics Interview Questions and Answers Part-2
11. How do you perform current sensing?
There are different methods to sense and measure current inside a circuit or a conductor some of the methods are mentioned below. Based on the load current rating and Isolation requirement, we have select one of the methods given below.
- Rogowski coil
- Flux Gate
- Current transformer
- Hall sensor
- Shunt resistor
12. Why do we need SPICE models?
SPICE is a computer simulation and modeling program used to mathematically predict the behavior of electronics circuits.
13. Why we need a Sample and Hold circuit?
A sample and hold circuit is an analog circuit that samples the voltage of a continuously varying analog signal and holds its value at a constant level for a specified minimum period of time.
Sample and hold circuits are commonly used in A/D converters, Communications circuits etc..
14. How can we detect a peak value of a waveform?
Using peak detector we can detect. The peak detector is a series connection of a diode and capacitor outputting a DC voltage equal to the peak value of the input signal.
15. What is the difference between rectifier and inverter?
An inverter and rectifier perform opposite functions in electronics circuits.
Rectifier converters Alternating current to DC current
The inverter converts Direct current to AC current
16. What is the difference between crystal and Oscillator or Resonators?
Oscillators are stand-alone clock generators while quartz Crystal or ceramic Resonators are just one part of the whole Oscillator design.
Ceramic Resonator and Quartz Crystal are Passive devices they alone can not generate a stable clock signal, both of them need some external circuitry around them to sustain oscillations.
Oscillators are Active devices and can generate clock independently without and external circuitry.
17. What is Common mode noise?
Common-mode noise in terms of ac power is the noise signal between the neutral and the ground conductor or Line and the ground conductor. This should not be confused with normal mode noise, which is referenced from the line (hot), and the neutral conductor.
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| Common mode noise |
18. What is Differential mode noise?
The differential mode noise is an electrical signal which appears in one or two conductors of a closed-loop, it appears in series with the desired signal while the current flows in opposite directions.
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| Differential mode noise |
Stray capacitance is the unintended and unwanted capacitance in a circuit.
Capacitance doesn't exist only within capacitors. In fact, any two surfaces at different electric potential, and that are close enough together to generate an electric field have capacitance and thus act as a capacitor. Such effects are often present within circuits even though they are not intended.
This unintended capacitance is referred to as stray capacitance, and it can result in a disruption of normal current flow within a circuit.
20. What is the Schmitt trigger?
Schmitt trigger is a comparator circuit with hysteresis implemented by applying positive feedback to the noninverting input of a comparator or differential amplifier. It is an active circuit that converts an analog input signal to a digital output signal.
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| Schmitt trigger |
