Electronics-Thyristors and Tranducers
Electronics-Thyristors and Tranducers
1. A TRIAC:
- can trigger only on positive gate voltages
- can trigger only on negative gate voltages
- cannot be triggered with gate voltages
- can be triggered by either a positive or a negative gate voltage
2. When checking a good SCR or TRIAC with an ohmmeter it will:
- show high resistance in both directions
- show low resistance with positive on anode and negative on cathode, and high resistance when reversed
- show high resistance with negative on anode and positive on cathode, and low resistance when reversed
- show low resistance in both directions
4. What causes the piezoelectric effect?
- heat or dissimilar metals
- pressure on a crystal
- water running on iron
- a magnetic field
5. A UJT has:
- two base leads
- one emitter lead
- two emitter leads and one base lead
- one emitter lead and two base leads
6. The only way to close an SCR is with:
- a trigger input applied to the gate
- forward breakover voltage
- low-current dropout
- valley voltage
7. What is an SCR?
- a PNPN thyristor with 3 terminals
- a PNPN thyristor with 4 terminals
- a PNP thyristor with 3 terminals
- an NPN thyristor with 3 terminals
8. The only way to close an SCR is with:
- a trigger input applied to the gate
- forward breakover voltage
- low-current dropout
- valley voltage
9. What type of application would use a photovoltaic cell?
- an automobile horn
- a TI 92 calculator
- a magnetic field detector
- a remote power source
10. The smallest amount of current that the cathode-anode can have, and still sustain conduction of an SCR is called the:
- maximum forward current
- maximum forward gate current
- holding current
- reverse gate leakage current