Reference no: EM133203264

1. Thyristors are regenerative and cannot operate in the linear mode.
2. Before the triac, designers used two SCRs in series to accomplish the triac function.
3. To protect the SCR from dv/dt false triggering, an LC snubber circuit is used.
4. The conduction angle is the angle in degrees when the SCR turns on.
5. Both the SCR holding current and the gate trigger current parameters decrease with increasing junction temperature.
6. Once a thyristor has been triggered, the trigger current can be removed.
7. The structure of the diac is PNP material with a slice on N-material at both ends.
8. The firing delay angle is equal to 180 degrees minus the firing angle.
9. The triac offers the designer an economical and versatile means of accurately controlling AC power.
10. Like the SCR, the Shockley diode remains in the on-state until the forward current drops below the holding current.
11. The main reasons sensors are used can be summarized as follows: 1. To protect humans and machines from harm. 2. For part identification and quality. 3. For problem analysis. 4. To produce the fastest production.
12. Photoelectric sensors have a range much greater than that of proximity-type sensors.
13. If you are required to select a sensor to detect a plastic part and you need the maximum distance possible, then you would choose an unshielded capacitive sensor.
14. Photoelectric sensor have five components that include a light source, light detector, logic circuit, lens, and output switching device.
15. Two of the five types of proximity sensors offered by vendors are wand and rectangular.
16. A part entering the electric field of a capacitive proximity sensor causes the sensor output to change.
17. Both inductive and capacitive proximity sensors can sense package contents through the packaging material.
18. Vision systems used in range-finding require the use of two or more cameras.
19. If you are required to select a sensor to detect an aluminum part and you need a very narrow sensing field, then you would choose an unshielded inductive sensor.
20. Inductive sensors can only detect parts that have some magnetic material present. F
21. The triac firing delay angle is equal to 180 degrees minus the conductive angle.
22. The PUT gate reference is device dependent, not circuit dependent.
23. The PUT is a four-layer device similar to the SCR.
24. Low-frequency operation is the most reliable for a triac.
25. New setting distance for proximity sensors require experiment data for the actual sensing distance to make the calculations.
26. Inductive type sensors use an electromagnetic field to sense the presence of a part.
27. Sensors are non-contact type devices, have electronics circuits to generate the measurement, have numerous output circuit options, are always faster than switches, and require an external source of power.
28. An inductive proximity sensor's output turns on when the internal oscillator starts oscillating but the capacitive proximity sensor operation is the opposite.
29. Vision systems can be used to count the number of holes or features on a part, but they are not capable of measuring the size of the features.
30. The two major components present in all photoelectric sensors are a source of light and a receiver to detect the light.
31. The most popular type of proximity sensor style is the cylindrical threaded barrel type.