1. The ________ can conduct current in either direction and is turned on when a breakover voltage is exceeded.
2. You need to design a relaxation oscillator circuit. The most likely device to use might be
3. Identify the diac symbol.
4. You have the schematic diagram of several types of circuits. Which of these circuits most likely uses a triac?
5. Identify the symbol for an SCS.
6. The ________ is like a diac with a gate terminal.
7. You have a need to use a device to trigger an SCR. A good one to use might be
8. The SCR can be triggered on by a pulse at the
9. Identify the symbol:
10. Identify the triac from the given figures.
11. Which of the following devices might best be used to control an electric motor?
12. What is the correct symbol for an SCR?
13. You have a light-dimmer circuit using an SCR. In testing the circuit, you find that IG = 0 mA and the light is still on. You conclude that the trouble might be one of the following:
14. How many semiconductor layers are thyristors constructed with?
15. Your boss has asked you to recommend a thyristor that will enable you to turn it on with a pulse and also turn it off with a pulse. Which of the following should you recommend?
16. An SCR acts to control the speed of an electric motor by ________ the ________ of the pulse delivered to the motor.
17. Which symbol represents a UJT?
18. The anode-to-gate voltage can be used to turn the PUT on or off.
19. In an SCR-based half-wave phase-control circuit, a diode is connected in series with the anode.
20. The SCS is turned on with the cathode gate, and turned off with the anode gate.
21. UJTs can only be used to trigger triacs, not SCRs.
22. The SCR is a device that can be triggered off by a pulse applied to the gate.
23. Thyristors are 4-layer semiconductor devices.
24. The diac can conduct current in either direction and is turned on when a breakover voltage is exceeded.
25. The triac is similar to an SCR, but it provides conduction for both halves of the ac wave.