Describe how a pneumatic timer works.
What will be an ideal response?
When a rod pushes against the bellows, air is forced out the check valve. Retraction of the bellows causes the contact to close. When the rod is pulled back, the spring pushes outward on the bellows. Before the bellows can expand, however, air must enter through the air inlet. The needle valve controls the rate at which air can enter the bellows and therefore the time required to expand the bellows and reopen the circuit contact.
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An advantage of using fiberglass duct instead of sheet metal is that _____.
a. fiberglass is heavier than sheet metal b. fiberglass can be used with only a thin layer of additional insulation c. fiberglass lowers the air leakage rate d. all fiberglass duct is flexible
? Most late-model transmissions use an ____________________ to regulate transmission or transaxle fluid line pressure.
Fill in the blank(s) with the appropriate word(s).
What is the potential for employment opportunities in landscaping during the twenty-first century?
What will be an ideal response?
When the prefix “M” (Mega) is used in a unit of measurement, such as 100 MHz, it means __________.
a. hundred b. thousand c. million d. billion