Using Electricity Flashcards

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1
Q

What is the formula for current gain?

A

Current gain = collector current/base current

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2
Q

What is an iron bar with a coil around it called?

A

A solenoid

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3
Q

What is a relay?

A

A relay is a switch

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4
Q

What does a relay do?

A

A relay uses a small current to switch on a much larger current, typically in order to protect a user of a device which draws a large current.

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5
Q

What does a diode do?

A

It allows current to flow in only one direction.

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6
Q

What is adding small amounts of other elements to silicon to change its electrical properties called?

A

Doping

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7
Q

What can silicon be doped with?

A

Phosphorus and boron.

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8
Q

What is forward bias?

A

This allows the diode to pass current in a circuit once the voltage has equalled or exceeded about 0.7 volts in the forward bias direction.

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9
Q

What is reverse bias?

A

Where the diode will not conduct electricity until about 1000V.

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10
Q

What materials can magnets attract to?

A
  1. Iron
  2. Some steels
  3. Nickel
  4. Cobalt
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11
Q

What is the advantage of using a relay over a transistor?

A

It is more robust.

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12
Q

Which bias does a LED give off light in?

A

Forward bias.

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13
Q

What two things do capacitors do?

A

Capacitors act as energy stores and they absorb energy in case of electricity spikes.

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14
Q

Where are capacitors used and why?

A

In computers to protect delicate electrical equipment.

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15
Q

What is the current gain formula?

A

Current gain = collector current/base current

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16
Q

How do you calculate the emitter current?

A

Collector current + base current

17
Q

What are transistors?

A

A transistor is a semiconductor device which can be used as an amplifier and a switch.