Electronic knowledge question and answer

What are the characteristics of semiconductor materials manufacturing electronic devices compared with traditional vacuum electronic devices?

Answer: The frequency characteristics are good, the volume is small, the power consumption is small, and the integrated products of the circuit are easy to be pocketed. In addition, it is particularly prominent in terms of strong seismic resistance and reliability; however, it is inferior to vacuum devices in terms of distortion and stability.

What are intrinsic semiconductors and impurity semiconductors?

A: Pure semiconductors are intrinsic semiconductors, and they are generally medium-priced elements in the periodic table. An impurity semiconductor is obtained by incorporating a high monovalent or low monovalent impurity element in an intrinsic semiconductor in a very small ratio.

Is a hole a kind of carrier? Does the hole move electrons when it conducts electricity?

A: No, but in its movement it can be equivalent to a carrier. When the hole is conductive, the electrons of the same amount move in the opposite direction.

What proportion of impurity semiconductor is generally doped in the intrinsic semiconductor?

A: Incorporate in a ratio of one-millionth.

What is an N-type semiconductor? What is a P-type semiconductor? What happens when two semiconductors are fabricated together?

A: Most semiconductors whose carriers are free electrons are called N-type semiconductors. Conversely, a semiconductor in which most carriers are holes is called a P-type semiconductor. After the P-type semiconductor is bonded to the N-type semiconductor, a P-N junction is formed.

What are the main physical characteristics of the PN junction?

A: Unidirectional conductivity and more sensitive temperature characteristics.

What are the names of the PN knot?

A: Space charge zone, barrier layer, depletion layer, etc.

Is the voltage and current applied to the PN junction linear? Why does it have unidirectional conductivity?

Answer: It is not linear. When the forward voltage is applied, the holes in the P region and the electrons in the N region attract each other under the electric field established by the forward voltage to produce a composite phenomenon, resulting in a thinning of the barrier layer and a forward current with voltage. The growth grows exponentially, and the conduction state is macroscopically. When the reverse voltage is applied, the situation is opposite to the above. The barrier layer becomes thicker, the current is almost completely zero, and the cutoff state is macroscopically. This is the unidirectional conduction characteristic of the PN junction.

Is there really no current when the PN junction is applied with a reverse voltage?

A: There is no current at all, and minority carriers generate very little reverse leakage current under the action of reverse voltage.

What are the most basic technical parameters of a diode?

A: Maximum rectified current

What are the main uses of diodes?

Answer: Rectification, detection, voltage regulation, etc.

How does the transistor control the collector current?

A: Through the current distribution relationship.

Can two diodes be reversed to form a triode? why?

Answer: No; the two diodes are connected to each other through the metal electrode, and there is no base area required for the triode.

What is the penetration current of the triode? What effect does it have on the amplifier?

Answer: When the base is open, the current between the collector and the emitter is the through current: where is the collector-base reverse leakage current, and both are generated by the movement of minority carriers, so The temperature is very sensitive and both will increase dramatically as the temperature rises. This has an adverse effect on the amplifier. Therefore, in actual work, they are required to be as small as possible.

What is the gate voltage of the triode?

A: The silicon tube is generally 0.5 volts. The bismuth tube is about 0.2 volts.

Does the amplification circuit amplify the electrical signal and the magnifying glass amplifies the object in the same sense?

A: Not the same.

What are the basic bias conditions in an amplifier consisting of a triode?

Answer: The emitter junction is positively biased; the collector junction is reverse biased.

What is the area of the triode input and output characteristic curve?

A: Generally divided into amplification area, saturation area and cut-off area.

What are the basic configurations of the amplifier circuit? What are they?

Answer: Three types are common emitter, common base and common collector.

In the common emitter amplifying circuit, what kinds of bias circuits are generally available?

A: There are upper base, partial pressure and set-base feedback.