Ham Radio Extra Questions Till 2020 Set E6C

E6C01 What is the function of hysteresis in a comparator?

• A. To prevent input noise from causing unstable output signals
• B. To allow the comparator to be used with AC input signal
• C. To cause the output to change states continually
• D. To increase the sensitivity

E6C02 What happens when the level of a comparator’s input signal crosses the threshold?

• A. The IC input can be damaged
• B. The comparator changes its output state
• C. The comparator enters latch-up
• D. The feedback loop becomes unstable

E6C03 What is tri-state logic?

• A. Logic devices with 0, 1, and high impedance output states
• B. Logic devices that utilize ternary math
• C. Low power logic devices designed to operate at 3 volts
• D. Proprietary logic devices manufactured by Tri-State Devices

E6C04 What is the primary advantage of tri-state logic?

• A. Low power consumption
• B. Ability to connect many device outputs to a common bus
• C. High speed operation
• D. More efficient arithmetic operations

E6C05 What is an advantage of CMOS logic devices over TTL devices?

• A. Differential output capability
• B. Lower distortion
• C. Immune to damage from static discharge
• D. Lower power consumption

E6C06 Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

• A. Larger bypass capacitors are used in CMOS circuit design
• B. The input switching threshold is about two times the power supply voltage
• C. The input switching threshold is about one-half the power supply voltage
• D. Input signals are stronger

E6C07 What best describes a pull-up or pull-down resistor?

• A. A resistor in a keying circuit used to reduce key clicks
• B. A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
• C. A resistor that insures that an oscillator frequency does not drive lower over time
• D. A resistor connected to an op-amp output that only functions when the logic output is false

E6C08 In Figure E6-5, what is the schematic symbol for a NAND gate?

• A. 1
• B. 2
• C. 3
• D. 4

E6C09 What is a Programmable Logic Device (PLD) ?

• A. A device to control industrial equipment
• B. A programmable collection of logic gates and circuits in a single integrated circuit
• C. Programmable equipment used for testing digital logic integrated circuits
• D. An algorithm for simulating logic functions during circuit design

E6C10 In Figure E6-5, what is the schematic symbol for a NOR gate?

• A. 1
• B. 2
• C. 3
• D. 4