FCC Commercial Element 8 pool, section 10

Subelement A

RADAR Principles

Section 10

Circuits-2

810A1

In the circuit shown in Fig. 8A4, U5 pins 1 and 4 are high and both are in the reset state. Assume one clock cycle occurs of Clk A followed by one cycle of Clk B. What are the output states of the two D-type flip flops?

A.
Pin 5 low, Pin 9 low.
B.
Pin 5 high, Pin 9 low.
C.
Pin 5 low, Pin 9 high.
Correct Answer
D.
Pin 5 high, Pin 9 high.

810A1

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810A2

If more light strikes the photodiode in Fig. 8A5, there will be:

A.
Less diode current.
B.
No change in diode current.
Correct Answer
C.
More diode current.
D.
There is wrong polarity on the diode.

810A2

Photodiode resistance drops when light strikes the diode, so more current flows and Answer C. is the right one.

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810A3

In the circuit shown in Fig. 8A6, which of the following is true?

A.
With A and B high, Q1 is saturated and Q2 is off.
Correct Answer
B.
With either A or B low, Q1 is saturated and Q2 is off.
C.
With A and B low, Q2 is on and Q4 is off.
D.
With either A or B low, Q1 is off and Q2 is on.

810A3

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810A4

What is the correct value of RS in Fig. 8A7, if the voltage across the LED is 1.9 Volts with 5 Volts applied and If max equals 40 milliamps?

A.
4,700 ohms.
B.
155 ohms.
Correct Answer
C.
77 ohms.
D.
10,000 ohms.

810A4

If If(max) = 40mA and V = 5V - 1.9V = 3.1V, then according to Ohms Law:

V = I x R

so:

R = V / I

R = 3.1V / 0.04A

R = 77Ω

Answer C. is the right answer.

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810A5

The block diagram of a typical RADAR system microprocessor is shown in Fig. 8A2. Choose the most correct statement regarding this system.

A.
The ALU is used for address decoding.
B.
General registers are used for arithmetic manipulations.
C.
The control unit executes arithmetic manipulations.
Correct Answer
D.
Address pointers are contained in the general registers.

810A5

Answer A. is right because General Registers can contain, inter alia, address pointers.

Answer A. is wrong because the ALU - Arithmetic Logic Unit is used for arithmetic

Answer B. is wrong because General Registers are not used for arithemtic.

Answer C. is wrong because the Control Unit synchronizes the internal components of a microprocessro but does not perform arithmetic operations.

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810A6

You are troubleshooting a component on a printed circuit board in a RADAR system while referencing the Truth Table in Fig. 8A8. What kind of integrated circuit is the component?

Correct Answer
A.
D-type Flip-Flop, 3-State, Inverting.
B.
Q-type Flip-Flop, Non-Inverting.
C.
Q-type Directional Shift Register, Dual.
D.
D to Q Convertor, 2-State.

810A6

The IC - Integrated Circuit is a FLip-Flop because when the input Dn goes High the corresponding output Q-Bar goes Low and flipping back and forth from High to Low and Low to High is what Flip-Flops are meant to do.

The Dn input stands for the nth Data input, so it's a D-Type Flip-Flop and this means the right answer is A.

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