True/False
Indicate whether the
statement is true or false.
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1.
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The on-delay relay is often referred to as DODO.
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2.
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Pneumatic timers are affected by variations in ambient temperature or
atmospheric pressure.
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3.
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Pneumatic timers are adjustable over a wide range of time periods.
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4.
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Instantaneous contacts change their positions immediately when the coil is
energized and change back to their normal positions immediately when the coil is de-energized.
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5.
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Clock timers are generally used to operate several switches.
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Completion
Complete each
statement.
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6.
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Timer relays are similar to other control relays in that they use a(n)
____________________ to control the operation of some number of contacts.
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7.
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The abbreviations TO and ____________________ are used with some control
schematics to indicate a time-operated contact.
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Figure 11-6 
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8.
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The accompanying figure shows a bellows-operated ____________________
timer.
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9.
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Clock timers use a small AC ____________________ motor similar to the motor
found in a wall clock to provide the time measurement for the timer.
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10.
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Cam times are also known as ____________________ timers.
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Short Answer
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11.
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What are the two general classifications in which time delay relays can be
divided?
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12.
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Briefly describe how pneumatic timers operate.
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13.
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List two advantages of clock timers.
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14.
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In cam timers, how is the operation of the switches controlled?
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15.
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What do electronic timers use as the time base?
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