100+ R&D Engineer Interview Questions and Answers

Answering questions related to ideal characteristics of opamp, CMRR, input impedance, impedance matching, MPTT, and significance of opamp in D-A and A-D convertors.

• Ideal characteristics of opamp include high gain, high input impedance, low output impedance, and low noise.

• CMRR stands for Common Mode Rejection Ratio and it measures the ability of an opamp to reject common mode signals.

• The practical significance of CMRR is that it helps in reducing noise and interference in the ...read more

Explanation of full wave bridge rectifier, transformer losses, filter usage, and Zener diode as regulator.

• Full wave bridge rectifier converts AC to DC using four diodes arranged in a bridge configuration

• Transformer losses occur due to core saturation and resistance in the windings

• Filters are used to smooth out the DC output and reduce ripple

• Zener diode operates in reverse breakdown region and maintains a constant voltage output

• Zener diode can be used as a voltage regulator in...read more

I would start by identifying the root cause of the crash and then work on finding a solution to fix it.

• First, I would analyze the crash dump to identify the error message or code that caused the crash.

• Then, I would review the software code to understand the context of the error and identify any potential bugs or issues.

• I would also check for any known issues or bugs that have been reported by other customers.

• Once I have identified the root cause of the crash, I would work on ...read more

Comparison of 8086 with present processors and why PC processors can't be used in mobiles

• 8086 had a 16-bit data bus and 20-bit address bus, while modern processors have 64-bit data bus and 48-bit address bus

• 8086 had a clock speed of 5-10 MHz, while modern processors have clock speeds in GHz

• Mobile processors are designed to be power-efficient and have lower clock speeds compared to PC processors

• Mobile devices use different storage technologies like eMMC, UFS, and NVMe SSDs

• Mobi...read more

Question on breadth first search, longest common subsequence, and output of code written on paper.

• Breadth first search is a graph traversal algorithm that visits all the vertices of a graph in breadth-first order.

• Longest common subsequence is the longest subsequence common to all sequences in a set of sequences.

• Output of code written on paper refers to writing code on paper and then analyzing the output without actually running the code.

Object class is inherited by each subclass separately in multiple levels of inheritance.

• Each subclass inherits the object class of its parent class.

• If a subclass has multiple parent classes, it inherits the object class of each parent class separately.

• Object class is the root class of all classes in Java and provides basic methods and properties.

• Example: Class C extends Class B, which extends Class A. Each class inherits the object class separately.

• Example: Class C extends Cl...read more

Dynamic memory allocation in C and C++ can be done using malloc, calloc, realloc and new operators.

• malloc() function is used to allocate a block of memory of specified size.

• calloc() function is used to allocate a block of memory and initializes it to zero.

• realloc() function is used to resize the previously allocated memory block.

• new operator is used in C++ to allocate memory for an object.

• Memory allocated using these functions should be freed using free() function in C and de...read more

The point where maximum intersections are happening in a 2D graph can be found by analyzing the overlapping regions of lines or curves.

• Identify all the lines or curves in the graph

• Determine the regions where these lines or curves overlap

• Count the number of intersections in each overlapping region

• Find the point with the highest number of intersections

Abstract classes are still relevant in Java 8 for shared state and constructor usage, despite interface enhancements.

• Abstract classes can have instance variables, while interfaces cannot.

• Example: An abstract class can define a common state for subclasses.

• Abstract classes can have constructors, allowing initialization of fields.

• Example: An abstract class can enforce a certain structure for subclasses.

• Interfaces are best for defining capabilities, while abstract classes are for...read more

Abstract classes are used when we want to provide a default implementation, while interfaces are used when we want to enforce a contract.

• Use abstract classes when you want to provide a default implementation for some methods.

• Use interfaces when you want to enforce a contract that must be implemented by the implementing class.

• Abstract classes can have constructors, while interfaces cannot.

• A class can implement multiple interfaces, but can only inherit from one abstract class.

• A...read more

I approach conflicts by actively listening, identifying the root cause, and finding a mutually beneficial solution.

• Listen to all parties involved and understand their perspectives

• Identify the root cause of the conflict

• Brainstorm potential solutions with all parties involved

• Find a mutually beneficial solution that addresses the root cause

• Communicate the solution clearly and ensure all parties are satisfied

Stacks can be implemented using two queues, while queues can be implemented using two stacks.

• To implement a stack using queues, we can use one queue for storing elements and another temporary queue for operations.

• To push an element onto the stack, we enqueue it to the temporary queue, then enqueue all elements from the main queue to the temporary queue, and finally swap the names of the two queues.

• To pop an element from the stack, we dequeue an element from the main queue.

• To ...read more

To handle huge amount of data efficiently, consider using distributed storage systems, data compression techniques, and data partitioning.

• Utilize distributed storage systems like Hadoop or Spark to store and process large volumes of data across multiple nodes

• Implement data compression techniques such as gzip or snappy to reduce storage space and improve data transfer speeds

• Partition data into smaller chunks based on key attributes to distribute workload and improve query perf...read more

Find all unique pairs in an array that sum to the same value.

• Use a hash set to track seen numbers and their complements.

• Iterate through the array and for each number, check if its complement exists.

• Store pairs in a result set to ensure uniqueness.

• Example: For array [1, 2, 3, 4], pairs are (1,3) and (2,2) for sum 4.

• Return pairs as an array of strings, e.g., ['(1,3)', '(2,2)'].

Rotate array clockwise K times, implement binary search

• Rotate the array by reversing the array and then reversing the first K elements and then reversing the remaining elements

• Implement binary search by dividing the array into two halves and comparing the middle element with the target

• Repeat the binary search until the target is found or the array is exhausted

Pointers are variables that store memory addresses. A dangling pointer is a pointer that points to a memory location that has been deallocated.

• Pointers are used to access memory directly

• They can be used to pass values by reference

• Dangling pointers can cause program crashes or unexpected behavior

Find max of multiple of 3 elements in an array with positive and negative values.

• Iterate through the array and keep track of the three largest positive and negative numbers.

• Multiply the three largest positive numbers and the three largest negative numbers by each other and find the maximum of the resulting products.

Cake can be cut into 8 equal pieces by making 3 cuts.

• Make two cuts to divide the cake into quarters, then make a third cut through all quarters to get 8 equal pieces.

• Each cut should be made perpendicular to the previous cut.

• The size of the cake does not matter as long as it is a cylindrical or rectangular shape.

OSI model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system.

• OSI model has 7 layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

• Each layer has a specific function and communicates with the layers above and below it.

• Linked list is a data structure that consists of nodes linked together in a sequence.

• Each node contains data and a pointer to the next node in the lis...read more

Identified a financial risk in project budgeting and implemented a risk management strategy to mitigate potential losses.

• Conducted a thorough analysis of project costs and identified discrepancies in budget forecasts.

• Engaged with stakeholders to discuss potential impacts of budget overruns on project timelines.

• Developed a revised budget plan that included contingency funds to address unforeseen expenses.

• Implemented regular budget reviews to monitor spending and adjust forecas...read more

To find if there is a cycle in a linked list, left view of a tree, Comparator vs Comparable in Java, and internal implementation of Hashmap.

• To find a cycle in a linked list, you can use Floyd's Tortoise and Hare algorithm.

• To get the left view of a tree, you can perform a level order traversal and print the first node at each level.

• Comparator in Java is used to compare objects based on custom criteria, while Comparable is an interface used to define natural ordering of objects...read more

Program to fetch second highest number from array

• Sort the array in descending order

• Return the second element of the sorted array

The working principle of the project developed earlier involved utilizing machine learning algorithms to analyze data and make predictions.

• Used supervised learning techniques to train the model

• Implemented feature engineering to improve model performance

• Utilized cross-validation to assess model accuracy

• Applied the trained model to new data for prediction

Some competitors of Schneider Electric include Siemens, ABB, and Eaton.

• Siemens

• ABB

• Eaton

I utilize various resources to stay informed about financial regulations and market trends, ensuring compliance and strategic insight.

• Subscribe to financial news outlets like Bloomberg and Reuters for real-time updates.

• Attend industry conferences and webinars to network and learn from experts.

• Follow regulatory bodies such as the SEC or FCA for official updates on regulations.

• Engage in online forums and professional networks like LinkedIn to discuss trends with peers.

• Read rese...read more

Passion for developing sustainable energy solutions and improving grid reliability.

• Desire to address climate change by promoting renewable energy sources

• Interest in optimizing power distribution systems for efficiency

• Drive to enhance grid stability and reliability through innovative solutions

An inverter is a device that converts DC power to AC power and vice versa in backup mode.

• Inverter converts DC power from a battery into AC power for household appliances.

• During backup mode, inverter converts AC power from grid into DC power to charge the battery.

• Common types of inverters include sine wave, modified sine wave, and square wave inverters.