SYSTEMS PREPARATION QUESTIONS 2008 - 3
V. Ryan © 2008
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The Theme Park owner has commissioned a model clown. The aim is to frighten younger visitors. A motor inside the clown drives the arms up and the arms return to their original position when the motor is off The motor is the output to a 555 timer circuit. The circuit also produces sound as the arms move. |
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There are two types of 555 timer. What is the name of the 555 circuit shown below? |
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| CIRCUIT NAME: ______________________________________ | ||
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| CIRCUIT NAME: 555 ASTABLE | ||
| Label the components on the circuit diagram below (A TO G). | ||
| ANSWER | ||
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The relay is causing major problems because an important component is missing. Name the component and draw its symbol in the correct position on the circuit diagram above. |
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| COMPONENT NAME: ______________________________ | ||
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| COMPONENT NAME: DIODE | ||
| What is the function of the component ? | ||
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The diode protects sensitive components such as the transistors from back E.M.F. When a current to a relay is removed the relay can emit current stored in its coils. This can be sent the wrong way round the circuit damaging components. The diode operates like a one way valve preventing this from happening. |
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