Engineering Questions with Answers - Multiple Choice Questions

# MCQs on ADC, DAC Interfacing

1 - Question

Why two pins for ground are available in ADC0804?
b) for controlling the analog and the digital pins of the controller
c) for both parts of the chip respectively
d) for isolate analog and digital signal

Explanation: Two grounds are available in ADC0804 to isolate analog signal from digital signal. This isolation provides accuracy in digital output.

2 - Question

What is the function of the WR pin?
a) its active high input used to inform ADC0804 to the end of conversion
b) its active low input used to inform ADC0804 to the end of conversion
c) its active low input used to inform ADC0804 to the start of conversion
d) its active high input used to inform ADC0804 to the start of conversion

Explanation: WR is active low input used to inform the ADC0804 to start the conversion process.

3 - Question

State which of the following statements are false?
a) CLK IN pin used for External Clock Input or Internal Clock with external RC element
b) INTR pin tells about the end of the conversion
d) None of the mentioned

Explanation: CLK IN pin is used to tell about the conversion time, INTR pin tells about the end of the conversion and ADC0804 has a resolution of 8 bits only so all three statements are true.

4 - Question

While programming the ADC0808/0809 IC what steps are followed?
a) select the analog channel, start the conversion, monitor the conversion, display the digital results
b) select the analog channel, activate the ALE signal (L to H pulse), start the conversion, monitor the conversion, read the digital results
c) select the analog channel, activate the ALE signal (H to L pulse), start the conversion, monitor the conversion, read the digital results
d) select the channel, start the conversion, end the conversion

Explanation: While programming the ADC0808/0809 IC firstly we need to select the channel from the A, B, C pins. Then we need to activate the ALE signal, this is needed to latch the address. Then we start the conversion from the WR pin. After monitoring the INTR pin we get to know about the end of the conversion. Then we activate the OE enable to read out data out of the ADC chip.

5 - Question

In ADC0808/0809 IC which pin is used to select Step Size?
a) Vref
b) Vin
c) Vref/2 & Vin
d) None of the mentioned

Explanation: Step Size is calculated by formula Vref/(2n). As ADC0808/0809 8-bit ADC value of n=8. Therefore formula becomes Vref/(28) = Vref/256. If Vref = 5V then Step Size will be 5/256 i.e. 19.53mV.

6 - Question

What is the difference between ADC0804 and MAX1112?
a) ADC0804 has 8 bits and MAX1112 has 1 bit for data output
b) ADC0804 is used for adc and dac conversions whereas MAX1112 is used for serial data transmissions
c) ADC0804 has 32 bits and MAX1112 has 3 bit for data output
d) None of the mentioned

7 - Question

Which of the following statements are true about DAC0808?
a) parallel digital data to analog data conversion
b) it has current as an output
c) all of the mentioned
d) none of the mentioned

Explanation: DAC0804 is used for parallel data to analog data conversion.

8 - Question

8 input DAC has ________
a) 8 discrete voltage levels
b) 64 discrete voltage levels
c) 124 discrete voltage levels
d) 256 discrete voltage levels

Explanation: For n input DAC has 2^n discrete voltage levels.

9 - Question

INTR, WR signal is an input/output signal pin?
a) both are output
b) both are input
c) one is input and the other is output
d) none of the mentioned

Explanation: INTR pin tells about the end of the conversion (output) and WR pin tells us to start the conversion (input).

10 - Question

What is the function of the SCLK pin in MAX1112?
a) It is used to bring data in
b) It is used to bring data out and send in the control byte, one at a time
c) It is used to get output clock
d) It is used to get serial output