What does DIAC stand for?
A
Diode for Alternating Current B
Dual Integrated AC C
Digital AC Amplifier Circuit D
Direct AC Converter
Analysis & Theory
**DIAC** stands for **Diode for Alternating Current**, a bidirectional trigger diode.
How many terminals does a DIAC have?
A
1 B
2 C
3 D
4
Analysis & Theory
DIAC has **two terminals** and no gate terminal.
What type of device is a DIAC?
A
Unidirectional B
Bidirectional C
Digital logic D
Rectifier
Analysis & Theory
**DIAC** is a **bidirectional** device that conducts in both directions after breakdown.
Which of the following is a typical application of a DIAC?
A
Rectification B
Amplification C
Triggering a TRIAC D
Battery charging
Analysis & Theory
DIAC is commonly used to **trigger a TRIAC** in light dimmers and AC controls.
What happens when the voltage across a DIAC exceeds its breakover voltage?
A
It starts oscillating B
It remains in off state C
It starts conducting D
It increases resistance
Analysis & Theory
When voltage exceeds breakover level, the DIAC **starts conducting**.
The V-I characteristic of DIAC is:
A
Linear B
Unidirectional C
Bidirectional and symmetrical D
Exponential
Analysis & Theory
**DIAC has a symmetric, bidirectional** V-I characteristic.
Which layer structure represents a DIAC?
A
PN B
PNP C
NPN D
PNPN
Analysis & Theory
DIAC has a **PNPN** structure but without a gate terminal.
DIAC is mainly used in:
A
DC motor drives B
Signal amplification C
Phase control circuits D
Logic circuits
Analysis & Theory
DIAC is ideal for **phase control** of power in AC circuits.
Which of the following devices is usually used with a DIAC?
A
SCR B
LED C
MOSFET D
TRIAC
Analysis & Theory
DIAC is used to **trigger TRIACs** by providing a sharp gate pulse.
DIAC conducts current when:
A
Voltage is less than breakover B
Voltage exceeds breakover in any direction C
Only positive voltage is applied D
Gate signal is provided
Analysis & Theory
DIAC conducts when **voltage exceeds breakover** in either direction (no gate needed).