Diode is a three layer semiconductor device that has two terminals. TRUE or FALSE2.The diode is said to be reversed biased when anode is more positive than the cathode. TRUE or FALSE.3.When cathode is more positive than the anode, the diode is said to be forward biased. TRUE or FALSE.4.During turn OFF of a diode, the charges stored in the diffusion region has to be increased. TRUE or FALSE.5.The bipolar junction transistor (BJT) is a two terminal device. TRUE or FALSE.6.The bipolar junction transistor (BJT) is a metallic device. TRUE or FALSE.7.The bipolar junction transistor (BJT) is a three layer device. TRUE or FALSE.8.Based on the doping type the two types of BJT are _ and .9.The ratio a collector current to the base current is given as ‘alpha’. TRUE or FALSE.10.Thyristor is a generic name for a three or more layer semiconductor device. TRUE or FALSE.11.MOSFET is a current control device. TRUE or FALSE.12.Application of a voltage to the anode cathode of an SCR will reverse-bias it.
The Correct Answer and Explanation is :
Here are the answers with explanations for each statement:
- FALSE – A diode is a two-layer semiconductor device (not three). It has a p-type layer and an n-type layer, and these form a p-n junction. It has two terminals: anode and cathode.
- FALSE – A diode is reverse biased when the cathode is more positive than the anode. In reverse bias, the current does not flow, and the diode acts as an open circuit.
- FALSE – A diode is forward biased when the anode is more positive than the cathode. In forward bias, the current flows through the diode.
- FALSE – During the turn-off of a diode, the charges stored in the diffusion region must be removed, not increased. This is to stop current flow, as the diode needs to become non-conductive when it turns off.
- FALSE – A BJT (Bipolar Junction Transistor) is a three-terminal device. The three terminals are emitter, base, and collector.
- FALSE – The BJT is not a metallic device. It is a semiconductor device made of three layers of semiconductor material (p-n-p or n-p-n).
- TRUE – The BJT is a three-layer device. It consists of three layers of semiconductor material, which can either be p-type or n-type, forming the emitter, base, and collector.
- NPN and PNP – The two types of BJTs are NPN and PNP, depending on the arrangement of the p-type and n-type materials.
- TRUE – The ratio of the collector current to the base current in a BJT is given as alpha (α), which is the current gain of the transistor.
- TRUE – A thyristor is a generic name for a semiconductor device with three or more layers. It typically has four layers (PNPN) and is used in switching applications.
- FALSE – A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a voltage-controlled device, not a current-controlled one. The current in a MOSFET is controlled by the voltage applied to the gate.
- Negative – Application of a negative voltage to the anode-cathode of an SCR (Silicon-Controlled Rectifier) will reverse bias it, preventing current flow.
Explanation:
Semiconductor devices like diodes, BJTs, MOSFETs, and thyristors are essential in controlling current flow. A diode only allows current to flow in one direction when forward biased and blocks it when reverse biased. BJTs are used for amplification, with NPN and PNP types differing in the direction of current flow. MOSFETs are voltage-controlled and offer faster switching for digital applications. Thyristors are used in power control because they can switch large amounts of current when triggered properly, and SCRs need a negative bias to stop current flow. These properties make semiconductors vital for a variety of electronic and power systems.