Resistors, lamps and diodes

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  • Created by: emews
  • Created on: 12-11-17 14:17
What are thermistors used for?
Thermistors are used as temperature sensors, for example in fire alarms. The resistance decreases as the temp increases.
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What are LDRs used for?
LDRs are used to detect light levels, for example in automatic security lights. The resistance decreases as the light intensity increases.
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What is the total resistance if two or more resistors are connected in series in a circuit.
When resistors are connected in series, the total resistance of two or more resistors is the sum of their individual resistance.
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What is the total resistance if two or more resistors are connected in parallel in a circuit.
When resistors are connected in parallel, the combined resistance of two or more resistors is less than that of either resistor by itself.
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What happens to the resistor of a lamp as the temperature increases?
The resistor of a lamp increases as the temperature increases.
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Filament lamps contain a thin coil of what?
Filament lamps contain a thin coil of wire called the filament.
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What are potentiometers?
Potentiometers are variable resistors with a resistance control that is adjusted once and then fixed.
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True or false? The current flowing through a filament lamp is not directly proportional to the voltage across it.
TRUE!
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What is a diode?
Diodes are electronic components which can be used to regulate the potential difference in circuits and to make logic gates.
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Explain the resistance of a diode.
Very high resistance in ONE direction. This means that the current can only flow in the other direction.
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What does LED stand for?
Light-emitting diode.
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What does an LED do?
Light-emitting diodes produce light when a current flows through them in the forward direction.
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What are LEDs used for?
LEDs and lamps are often used for indicator lights in electrical equipment such as computers and television sets.
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What are transistors?
Transistors are tiny electronic switches and amplifiers.
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What are the 3 main uses of a transistor?
As an electronic switch within a circuit, to switch on another part of a circuit when a change in resistance is detected, to receive signals from low current devices and use these to turn on high current devices.
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What is a relay?
A relay is a special type of switch surned on and off by an electromagnet
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What is a capacitor and what can it do?
A capacitor can store an electrical charge. Capacitors can be used to convert AC into DC. They can also be used to filter out fluctuations in a signal.
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Other cards in this set

Card 2

Front

What are LDRs used for?

Back

LDRs are used to detect light levels, for example in automatic security lights. The resistance decreases as the light intensity increases.

Card 3

Front

What is the total resistance if two or more resistors are connected in series in a circuit.

Back

Preview of the front of card 3

Card 4

Front

What is the total resistance if two or more resistors are connected in parallel in a circuit.

Back

Preview of the front of card 4

Card 5

Front

What happens to the resistor of a lamp as the temperature increases?

Back

Preview of the front of card 5
View more cards

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