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Design and Technology

Electronics

1.

The symbol I in electronic calculations represents:

Voltage

Resistance

Current

2.

What unit is resistance measured in?

amps

ohms

volts

3.

Which of the following is equal to 100 microfarads?

0.001 farads

0.0001 farads

0.00001 farads

4.

The current passing though a resistor is 20 milliamps. The value of the resistor is 100 ohms. Calculate the potential difference across the resistor.

2 volts

5 volts

2,000 volts

5.

Two resistors, R1 and R2, are in series. R1 has a value of 330 ohms and R2 has a value of 470 ohms. Calculate the combined resistance.

194 ohms

400 ohms

800 ohms

6.

A potential divider has a total potential difference across it of 10 volts. The value of the resistor R1 is 2,000 ohms and R2 is 3,000 ohms. Calculate the output voltage.

1.5 volts

6 volts

7.

A simple timer circuit contains a 10 kilo-ohm resistor and a 100 microfarad capacitor. Calculate the time constant.

1 second

10 seconds

1,000 seconds

8.

An astable circuit contains components with the following values: R1 40 kilo-ohms, R2 60 kilo-ohms and a 100 microfarad capacitor. Calculate the mark time.

1.67

4.158 seconds

6.93 seconds

9.

An astable circuit has a pulse that is high for 3 seconds and low for 2 seconds. Calculate the mark/space ratio.

0.66

1.5

5

10.

An operational amplifier has a feedback resistor of value 3.3 kilo-ohms and a 1 kilo-ohm input resistor. Calculate its gain.

-3.3

2.3

3.3