29.  Which semi-conductor deviceacts like a diode and two resistors?
A. SCR
B. triac
C. diac
D. UJT

---

30. Which semiconductor device behaves like two SCRs?
A. UJT
B. triac
C. JFET
D. MOSFET

---

31. An SCR is a semiconductor device made up of
A. four N-type layers
B. two P-type and three N-type layers
C. two P-type and two N-type layers
D. three P-type and one N-type layer

---

32.  An SCR conducts appreciable current when
A. anode and gate are both negative with respect to cathode
B. anode and gate are both positive with respect to cathode
C. anode is negative and gate is positive with respect to cathode
D. gate is negative and anode is positive with respect to cathode

---

33. After firing an SCR, the gating pulse is removed. The current in the SCR will
A. remain the same
B. immediately fall to zero
C. rise up
D. rise a little and then fall to zero

---

34. Which device acts like an NPN and a 'PNP transistor connected base-to-base and emitter-to-collector?
A. triac
B. UJT
C. disc
D. SCR

---

35.  An SCR may be considered to be ? diode back-to-back consisting of an anode, cathode and ?
A. 2, plate
B. 3, plate
C. 3, gate
D. 4, base

---