Design of Two Flashing Lights

Objectives :

• Design a circuit from a written statement of requirements.

• Connect the circuit in the laboratory after the design has been approved.

LABORATORY EXERCISE

Name __________ Date __________

Materials Required

Materials depend on the circuit design In the space provided in Ill. 1, draw a schematic diagram of a circuit that will fulfill the following requirements. Use two separate timers. Don't use an electronic timer set in the repeat mode. Remember that there is generally more than one way to design any circuit.

Try to keep the design as simple as possible. The fewer components a circuit has, the less it's likely to fail.

1. An on-off toggle switch is used to connect power to the circuit.

2. When the switch is turned on, two lights will alternately flash on and off. Light #1 will be turned on when light #2 is turned off. When light #1 turns off, light #2 will turn on.

3. The lights are to flash at a rate of on for 1 second and off for 1 second.

When completed, have your instructor approve the design. After the design has been approved, connect it in the laboratory.

QUIZ :

1. When designing a control circuit that requires the use of a timing relay, what type of timer is generally used during the design?

2. Should schematic diagrams be drawn to assume that the circuit's energized or de energized?

3. Explain the difference between a schematic and a wiring diagram.

4. In a forward-reverse control circuit, a normally closed F contact is connected in series with the R starter coil, and a normally closed R contact is connected in series with the F starter coil. What is the purpose of doing this and what is this contact arrangement called?

5. What type of overload relay isn't sensitive to changes in ambient temperature?