Serial Port Communication 1. What actually are the DB9, DB25 ports available in our computers? a) they are connectors used to transfer data either serially or parallelly b) they are the RS232 connectors used to connect two incompatible devices c) they are the TTL logic connector pins used for communication d) they are just data transfer pins used to transfer the data Answer: they are the RS232 connectors used to connect two incompatible devices 2. What does RI handshaking signal refer to according to the RS232 logic? a) if this logic is high then a receive interrupt is generated b) this pin is high during transmission c) this pin is high during a reception in order to tell that the device is busy at this particular time d) none of the mentioned Answer: this pin is high during a reception in order to tell that the device is busy at this particular time 3. What is the major difference between a MAX232 and a MAX233 device? a) one has one serial port other has two b) one has inbuilt UART

  AVR Microcontroller I/O Port Programming and Addressing Modes 1. In AVR, which registers are there for the I/O programming of ports? a) PORT b) PIN c) DDR d) All of the mentioned Answer: All of the mentioned 2. The data will not go from the port registers to the pin unless: a) DDR register of that port is set to 0 b) PORT register of that port is set to 1 c) DDR register of that port is set to 1 d) PORT register of that port is set to 0 Answer: DDR register of that port is set to 1 3. On reset DDR registers of all ports are set to: a) 0 b) 1 c) None of the mentioned d) 0 & 1 Answer: 0 4. Which of the following statements are correct? a) PIN register of a port is used to bring data into CPU from pins b) PORT register is used to send data out to pins c) DDR register is used to control the direction of a port d) All of the mentioned Answer: All of the mentioned 5. In the AVR family, all I/O ports have 8 pins? a) true b) false c) none of the mentioned d) can’t be determined Answer: f

 How to test an Op Amp IC? Operational Amplifiers are widely used in electronic circuits as amplifiers, comparators, voltage follower, summing amplifier etc. Most of the commonly used Op Amps like 741, TL071, CA3130, CA3140 etc have same pin configurations. Hence this tester is useful to check the working of the Op Amp during trouble shooting or servicing. It is an easy to make tool which is essential in the work bench of a hobbyist or technician. The tester is wired around an 8 pin IC base into which the IC to be tested can be inserted. Pin 2 (inverting input of IC) is connected to a potential divider R2, R3 that gives half supply voltage to pin 2. Pin 3 (None inverting input) of IC base is connected to the VCC through R1 and a Push to on switch. Output pin 6 is used to connect the visual indicator LED via the current limiting resistor R4. The design is a voltage comparator. Insert the IC in to the socket with correct orientation. The notch at the left side of the IC should match with

   Operational Amplifier (Op-amp) What is an Operational Amplifier (Op-amp)? An operational amplifier is an integrated circuit that can amplify weak electric signals. An operational amplifier has two input pins and one output pin. Its basic role is to amplify and output the voltage difference between the two input pins. An operational amplifier (op amp) is an analog circuit block that takes a differential voltage input and produces a single-ended voltage output. Pin configuration V+: non-inverting input V−: inverting input Vout: output VS+: positive power supply VS−: negative power supply Operational Amplifier Clasifications There are four ways to classify operational amplifiers: Voltage amplifiers take voltage in and produce a voltage at the output. Current amplifiers receive a current input and produce a current output. Transconductance amplifiers convert a voltage input to a current output. Transresistance amplifiers convert a current input and produces a voltage output. Op-amp ch

  Active Filter active filter is a type of analog circuit implementing an electronic filter using active component, typically an amplifier. Amplifiers included in a filter design can be used to improve the cost, performance and predictability of a filter. What is an Active Filter? The filter is an electric n/w in any circuit theory, that used to change either phase or amplitude of signal characteristics with respect to its frequency. Ideally, this will not include any new frequency to the i/p nor it will alter the frequency component of that signal. An Active Filter utilizes an operational amplifiers along with various electronic components like resistors, capacitors for the filtering. Op-Amps are used to allow easily to make many types of active filters.An Amplifier stops the load impedance from affecting the filter characteristics. The form of the response, duality factor and tuned frequency and can often set with inexpensive variable resistors. In these filter circuits we can alter

Cell A cell is defined as the smallest, basic unit of life that is responsible for all of life’s processes. Functions of Cell A cell performs these major functions essential for the growth and development of an organism. Important functions of cell are as follows: Provides Support and Structure All the organisms are made up of cells. They form the structural basis of all the organisms. The cell wall and the cell membrane are the main components that function to provide support and structure to the organism. For eg., the skin is made up of a large number of cells. Xylem present in the vascular plants is made of cells that provide structural support to the plants. Facilitate Growth Mitosis In the process of mitosis, the parent cell divides into the daughter cells. Thus, the cells multiply and facilitate the growth in an organism. Allows Transport of Substances Various nutrients are imported by the cells to carry out various chemical processes going on inside the cells. The waste produced