LOGCAST BOARD EXAM Questions
Reli, Jr. Michael Sablan, Allen Samonte, Kenneth Vitug, Marines Valencia, Lyann Angel 1.
Given:
A = WXY(W + Z). Determine the output of the circuit A i f W=0, X=1, Y=1, and Z=0. (November, 2002) a. 0 b. 1 c. 2 d. 10 2. A sum term is that contains all variables in completed form is called: (November, 2002) a. minterm b. maxterm c. product term d. none of the above. 3. Four cascaded cascaded toggle flip-flop divide the input frequency by: a. 2 b. 4 c. 8 d. 16 4. Registers and counters are similar in the sense that they both: (November, 2002) a. count pulses b. store binary information c. are made from an array of flip-flops and gates integrated on a single chip d. are, in fact, shift registers 5. The scale of integration of an IC depends in the number of ________ ________ in the the package. (November, 2002) a. transistors b. diodes c. gates d. pins 6. The number 144.4410 is what in octal? (November, 2002) a. 220.348 b. 908 c. 49.568 d. none of these 7. If the inputs to an RS flip-flop are R-low, S-low, Enable-high, Enable-high, Preset-low, Clear-high, the output will be: (November, 1997) a. high b. low c. undetermined d. illegal inputs combination 8. An OR gate can be constructed by connecting: (November, 1997) a. an AND gate is cascaded with NOT gate b. one or more NOT gates inputted to an AND gate c. one or more more NOT gates inputted inputted to a NOR gate d. one or more NOT gates inputted to a NAND gate 9. In a parallel adder: (November, 1997) a. all bits are ar e added simultaneously b. all bits are added sequentially, LSB first c. all bits are added sequentially, MSB first d. the bits cant be added 10. An astable multivibrator has: (November, 1997) a. one stable state b. no stable state c. two stable states d. three stable states
Laxina, Jett Nuqui, Godofredo Roxas, Carlos Javier Valiente, John Ernest Yalung, Mary Wella 1. A CMOS with parallel PMOS and complementary series NMOS is equivalent to logical. (March 1996) a. AND gate b. NOR gate c. OR gate d. NAND gate 2. Which is not true regarding a CMOS inverter? (April 1998) a. Full logical zero and one levels are presented at the output b. Essentially no current flows for logic zero and logic one input c. Increasing the input frequency, decreases the power dissipation d. For devices of similar dimensions PMOS is lower than NMOS 3. Which is not an advantage of CMOS over TTL logic family? (April 1997) a. Greater packing density b. Greater fan out c. Lower propagation delay d. Lower power dissipation 4. A CMOS with series PMOS and complementary parallel NMOS is equivalent to logical (Nov 2008) a. AND gate b. OR gate c. NAND gate d. NOR gate 5. Which of the following is the probable output if all inputs of a TTL gate are binary one? (Nov 2008) a. Binary one b. Interminate c. Determinate d. Binary zero 6. An encoder is an MSI (medium scale integration) circuit that (Nov 1996) a. Selects a given output on binary input code b. Provides a storage of a certain number of binary bits c. Provides for delivery one of two or more inputs to an output d. Provides an output that corresponds to which a set of input line is true 7. A single digital word storage device is called: (Sep 1984) a. Gate b. Clock c. Timer d. Register 8. For an RS flip-flop made of NAND gates that race conditions happens when (Sept 1984) a. S=1, R=0 b. S=R=1 c. S=0, R=1 d. S=R=0 9. The memory element used in clocked sequence logic ci rcuit is (March 1996) a. Gate b. flip-flop c. static RAM d. dynamic RAM 10. A circuit that detects bit errors in a binary word is called a (November 1990) a. Comparator b. ex-NOR c. decoder d. parity checker Group
Maricar 1. _____ refers to a circuit that stores pulses and produces an output pulse when a specified number of pulses are stored. (March 1996) a. Counter b. register c. flip-flop d. buffer 2. The output pulses of a logic pulser _______. (Nov 1997) a. Can damage logic circuits b. Are too narrow for the logic probe to respond to c. Can only force high nodes to low d. Can be used to overdrive logic nodes high or low 3. What do you call a circuit that changes pure binary code into ACII? (March 2006)
a. Decoder b. encoder c. demultiplexer d. code converter 4. _________ is a single bit comparator. (Nov. 1997) a. Wired OR b. Exclusive OR c. NOR gate d. Exclusive NOR 5. How many symbols are used in octal digital number system? (Nov 1997) a. 16 b. 4 c. 8 d. 2 6. A solid state device which only gives a 1 output if all inputs are also 1 is called (1995) a. AND gate b. NAND gate c. NOR gate d. OR gate 7. Speed of a logic circuit is normally expressed as (1996) a. Logic levels b. speed immunity c. propagation delay d. power consumption 8. What is the equivalent of decimal number 11 in binary? (Nov. 1996) a. 1101 b. 1110 c. 1111 d. 1011 9. What is the is decimal 36020 equivalent to hexadecimal? (Nov 1997) a. 8CB4 b. 88BC d. 8BC8 d. 884C 10. What is the function of a flip-flop as logic element? (Nov, 1997) a. Stores binary data b. generates clock signal c. relay data d. makes decision
Group
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4. 5.
6. 7. 8. 9.
Rachelle Static memory will store information (Nov 1996) a. As long as power is applied to the memory b. Even when power is not applied to the memory c. As long as power is applied and the memory is refreshed periodically d. When power is applied at regular intervals What is the reason why more cells can be stored in a given area with dynamic cells (Mar 1996) a. They consume less power b. They are smaller c. They are larger d. They travel faster A _______ is a solid state memory device, which depends on the magnetic polarization of domains, usually in a garnet type material. (Nov 1997) a. Magnetic disk b.magnetic core c. magnetic bubble d. magnetic drum _________ are non-semiconductor devices still used in digital memories. (Nov 1996) a. Gates b. flip-flops c. Relay d. Magnetic cores The density of data recorded on magnetic tape is measured in (Nov 1996) a. Bit stuffing rate b. Bit error rate c. Bits per inch d. Bits per second A memory circuit that has 9 addresses has how many storage locations? (Nov 1996) a. 1024 b. 256 c. 512 d. not determined by sets of input ________ refers to BCD counter. (November 1995) a. Decade counter b. shift register c. frequency divider d. binary counter ______________ is a byte data stored in a memory location. (Nov 1995) a. 8 bits b. memory word c. character d. 4 bits What is the equivalent of hexadecimal 1A in decimal (Nov 1996)
a. 27 b. 40 c. 26 d. 42 10. A memory circuit that has a 9 address inputs has how many storage location? (Nov 1996) a. not determined by no. of inputs b. 512 c. 1024 d. 256
Cura, Daryl De Guzman, Jesmark Anthony Figueroa, Marlon O. Mallari, Arvin Cedric Q. Mallari, Juriel Jr. Mendoza, Harmond 1. Refers to the increased use of data conversion circuits as a result of increased application. (Guidebook in Electronics Engineering, November 1995) a) Op Amps b) Linear circuit c)
Computers
d) Digital equipment 2. What is a group of circuit that provides timing and signals to all operation in the computer? (Guidebook in Electronics Engineering, March 1996) a) Output unit b) Memory unit c)
Control unit
d) Input unit 3. Refers to the part of computer that performs mathematical operations. ( Guidebook in Electronics Engineering, March 1996) a) CPU b) Flip-flop c)
Assembly language
d) ALU 4. What does ALU which carries arithmetic and logic operations process? (Guidebook in Electronics Engineering, November 1996) a) Binary coded decimal b) Hexadecimal numbers c)
Octal numbers
d) Binary numbers 5. What is the smallest part of a computer language? ( Guidebook in Electronics Engineering, November 1995) a) Binary b) Byte c)
Bit
d) Word
6. A digital word consisting of only four bits is called a (Guidebook in Electronics Engineering, March 1996) a) Dibit b) Quad c)
Pixel
d) Nibble 7. How many symbols does hexadecimal number system used? ( Guidebook in Electronics Engineering, March 1996) a) 16 b) 4 c)
8
d) 32 8. Which of the following is not used in hexadecimal digital symbols? ( Guidebook in Electronics Engineering, November 1997) a) A b) C c)
H
d) F 9. What is the equivalent of decimal 7 in octal? (Guidebook in Electronics Engineering, November 1997) a) 21 b) 49 c)
7
d) 14 10. What level is used to represent logic 0 in negative logic circuit? ( Guidebook in Electronics Engineering, November 1995) a) High level b) Low level c)
Negative transition level
d) Positive transition level Cunanan, Christian Alex David, Fides marie Nunag, Mark Voltaire Manaloto, Arman Jose Sicat, Kathleene 1. In binary number, shifting the binary point one place to the right (November, 1997) a. Multiplies by two b. Divides by two c. Decrease by ten d. Increase by ten 2. The 2s complement of 10002 (November, 1997) a. 0111
b. 0101 c. 1000 d. 1001 3. The 15s complement of ABBA16 (November, 1997) a. BABA16 b. 123416 c. 544516 d. None of these 4. The number 128 is equivalent to decimal (November, 1997) a. 12 b. 20 c. 10 d. 4 5. What is the logic circuit having two or more inputs but only one output, with high output if any or all inputs are high, with low output only if all inputs are low? ( Guidebook in Electronics Engineering, March 1996) a.
AND gate
b. OR gate c.
NOR gate
d. NAND gate 1. How many bits are required to represent an 8-digit decimal number in BCD? (November, 1997)
2.
3. 4.
5.
a. 255 b. 4 c. 32 d. 256 The chief reason why digital computers use complement of subtraction is that it (November, 1997) a. Simplifies their circuit b. Is a very simple process c. Can handle negative numbers easily d. Avoid direct subtraction Solve for x in the given (152)8 = (211)x a. 8 b.7 c. 9 d. 6 In excess-3 code, each coded number is in the BCD code. (November, 1997) a. Four larger b. Three smaller c. Three larger d. Much larger The output of a toggle flip flop is the frequency of its input. (November, 1997) a. Twice b. Half c. Thrice d. One-third
Yabut, Alex Group 1. ________ is a device that stay on once triggered and store on or two conditions as a digital circuit (Nov. 1995) a. Gate b. latch c. integer d. oscillator 2. In shift registers made up of several flip-flops, the circuit signal indicates (Nov. 1995) a. A bit of information stored in the flip-flop b. Information of time c. What time is it
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d. When to shift a bit of data from input of the flip-flop to the output When a logic circuit rejects an unwanted signal, this is termed as (March 1996) a. Logic levels b. Noise margin c. Power consumptions d. Propagation delay Clock periods are measured from (Nov. 1997) a. The high level to the low level b. The low level to the high level c. Similar points in the clock waveform d. The clock pulse at 50% of its low or high levels What is the higher voltage level in digital gates and flip-flop circuits (Apr, 1998) a. Yes or One b. One or zero c. Zero or no d. Yes or no Refers to the digital interface in which data characteristics are i ndividually synchronized an may be sent at a time (Apr.1998) a. Half-duplex b. asynchronous c. synchronous d. simplex To cause a three-state buffer to output 0=1 levels, the following must be true. (Nov.1997) a. The output enable must be false b. The output enable must be true c. The information must have been stored in the buffer d. The signal OE must be at logic 1 Refers to the class of logic circuit containing flip-flop (Nov, 1996) a. combinational b. sequential c. linear d. feedback What is the process used to describe analog-to-digital conversion? (Nov, 1997) a. binarize b. linearize c. digitize d. analogize Which is not a type of flip-flop? (Apr. 1998) a. RS b. latch c. D d. Register
