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3-30. What is the main difference between the
TRIAC and the SCR?
1. The SCR requires a higher input
voltage than the TRIAC
2. The TRIAC requires a higher input
voltage than the SCR
3. The TRIAC controls and conducts
current during both alternations of an
ac cycle, while the SCR controls and
conducts current during only one
alternation
4. The SCR controls and conducts
current during both alternations of an
ac cycle, while the TRIAC controls
and conducts currents during only one
alternation
3-31. What name is given to a group of devices
that either produce light or use light in
their operation?
1. Optoelectronic
2. Ophthalmology
3. Optokenetic
4. Optometry
3-32. In optoelectronic devices, what do the
initials LED stand for?
1. Low-emitting diode
2. Low-emitting device
3. Light-emitting diode
4. Light-emitting device
3-33. What determines the color of light emitted
by an LED?
1. The type of incandescent bulb used
2. The type of material used
3. The type of bias used
4. The type of fluorescent bulb used
3-34. What is the standard schematic symbol
used to designate LEDs?
1. An incandescent bulb with arrows
pointing toward the light
2. An incandescent bulb with arrows
pointing away from the light
3. A diode with two arrows pointing
toward the cathode
4. A diode with two arrows pointing
away from the cathode
3-35. The circuit symbols for all optoelectronic
devices have arrows pointing either
toward them or away from them. When
the arrows point toward the symbol, what
does this indicate?
1. The device produces light
2. The device uses light
3. The device requires current flow
4. The device produces current flow
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